diff --git a/_config/backtrace.yml b/_config/backtrace.yml
index fb19e77fd..07808fc83 100644
--- a/_config/backtrace.yml
+++ b/_config/backtrace.yml
@@ -28,7 +28,8 @@ SilverStripe\Dev\Backtrace:
     - ['SilverStripe\Security\PasswordEncryptor_Blowfish', 'encryptA']
     - ['SilverStripe\Security\PasswordEncryptor_Blowfish', 'encryptX']
     - ['SilverStripe\Security\PasswordEncryptor_Blowfish', 'encryptY']
-    - ['SilverStripe\Security\PasswordValidator', 'validate']
+    - ['SilverStripe\Security\Validation\RulesPasswordValidator', 'validate']
+    - ['SilverStripe\Security\Validation\EntropyPasswordValidator', 'validate']
     - ['SilverStripe\Security\RememberLoginHash', 'setToken']
     - ['SilverStripe\Security\Security', 'encrypt_password']
     - ['*', 'checkPassword']
diff --git a/_config/passwords.yml b/_config/passwords.yml
index fc865200a..04d27a4cb 100644
--- a/_config/passwords.yml
+++ b/_config/passwords.yml
@@ -2,12 +2,5 @@
 Name: corepasswords
 ---
 SilverStripe\Core\Injector\Injector:
-  SilverStripe\Security\PasswordValidator:
-    properties:
-      MinLength: 8
-      HistoricCount: 6
-
-# In the case someone uses `new PasswordValidator` instead of Injector, provide some safe defaults through config.
-SilverStripe\Security\PasswordValidator:
-  min_length: 8
-  historic_count: 6
+  SilverStripe\Security\Validation\PasswordValidator:
+    class: 'SilverStripe\Security\Validation\EntropyPasswordValidator'
diff --git a/composer.json b/composer.json
index 8db93b4ad..f4ac18e47 100644
--- a/composer.json
+++ b/composer.json
@@ -50,7 +50,7 @@
         "symfony/mailer": "^7.0",
         "symfony/mime": "^7.0",
         "symfony/translation": "^7.0",
-        "symfony/validator": "^7.0",
+        "symfony/validator": "^7.1",
         "symfony/yaml": "^7.0",
         "ext-ctype": "*",
         "ext-dom": "*",
diff --git a/src/Control/Email/Email.php b/src/Control/Email/Email.php
index c7c350906..aa8bddd5c 100644
--- a/src/Control/Email/Email.php
+++ b/src/Control/Email/Email.php
@@ -4,14 +4,13 @@ namespace SilverStripe\Control\Email;
 
 use Exception;
 use RuntimeException;
-use Egulias\EmailValidator\EmailValidator;
-use Egulias\EmailValidator\Validation\RFCValidation;
 use SilverStripe\Control\Director;
 use SilverStripe\Core\Config\Configurable;
 use SilverStripe\Core\Environment;
 use SilverStripe\Core\Extensible;
 use SilverStripe\Core\Injector\Injectable;
 use SilverStripe\Core\Injector\Injector;
+use SilverStripe\Core\Validation\ConstraintValidator;
 use SilverStripe\ORM\FieldType\DBField;
 use SilverStripe\Model\ArrayData;
 use SilverStripe\View\Requirements;
@@ -22,6 +21,8 @@ use Symfony\Component\Mailer\MailerInterface;
 use Symfony\Component\Mime\Address;
 use Symfony\Component\Mime\Email as SymfonyEmail;
 use Symfony\Component\Mime\Part\AbstractPart;
+use Symfony\Component\Validator\Constraints\Email as EmailConstraint;
+use Symfony\Component\Validator\Constraints\NotBlank;
 
 class Email extends SymfonyEmail
 {
@@ -63,16 +64,17 @@ class Email extends SymfonyEmail
     private bool $dataHasBeenSet = false;
 
     /**
-     * Checks for RFC822-valid email format.
-     *
-     * @copyright Cal Henderson <cal@iamcal.com>
-     *    This code is licensed under a Creative Commons Attribution-ShareAlike 2.5 License
-     *    http://creativecommons.org/licenses/by-sa/2.5/
+     * Checks for RFC valid email format.
      */
     public static function is_valid_address(string $address): bool
     {
-        $validator = new EmailValidator();
-        return $validator->isValid($address, new RFCValidation());
+        return ConstraintValidator::validate(
+            $address,
+            [
+                new EmailConstraint(mode: EmailConstraint::VALIDATION_MODE_STRICT),
+                new NotBlank()
+            ]
+        )->isValid();
     }
 
     public static function getSendAllEmailsTo(): array
@@ -117,7 +119,7 @@ class Email extends SymfonyEmail
         $addresses = [];
         if (is_array($config)) {
             foreach ($config as $key => $val) {
-                if (filter_var($key, FILTER_VALIDATE_EMAIL)) {
+                if (static::is_valid_address($key)) {
                     $addresses[] = new Address($key, $val);
                 } else {
                     $addresses[] = new Address($val);
diff --git a/src/Control/HTTPRequest.php b/src/Control/HTTPRequest.php
index 160e450d3..dbe4f5351 100644
--- a/src/Control/HTTPRequest.php
+++ b/src/Control/HTTPRequest.php
@@ -7,6 +7,8 @@ use BadMethodCallException;
 use InvalidArgumentException;
 use SilverStripe\Core\ClassInfo;
 use SilverStripe\Core\ArrayLib;
+use Symfony\Component\Validator\Constraints\Ip;
+use Symfony\Component\Validator\Constraints\IpValidator;
 
 /**
  * Represents a HTTP-request, including a URL that is tokenised for parsing, and a request method
@@ -810,7 +812,8 @@ class HTTPRequest implements ArrayAccess
      */
     public function setIP($ip)
     {
-        if (!filter_var($ip, FILTER_VALIDATE_IP)) {
+        // We can't use ConstraintValidator here because it relies on injector and the kernel may not have booted yet.
+        if (!IpValidator::checkIp($ip, Ip::ALL)) {
             throw new InvalidArgumentException("Invalid ip $ip");
         }
         $this->ip = $ip;
diff --git a/src/Control/Middleware/TrustedProxyMiddleware.php b/src/Control/Middleware/TrustedProxyMiddleware.php
index e99064691..c2abf750e 100644
--- a/src/Control/Middleware/TrustedProxyMiddleware.php
+++ b/src/Control/Middleware/TrustedProxyMiddleware.php
@@ -3,7 +3,10 @@
 namespace SilverStripe\Control\Middleware;
 
 use SilverStripe\Control\HTTPRequest;
+use SilverStripe\Core\Validation\ConstraintValidator;
 use Symfony\Component\HttpFoundation\IpUtils;
+use Symfony\Component\Validator\Constraints\Ip;
+use Symfony\Component\Validator\Constraints\NotBlank;
 
 /**
  * This middleware will rewrite headers that provide IP and host details from an upstream proxy.
@@ -220,14 +223,14 @@ class TrustedProxyMiddleware implements HTTPMiddleware
 
         // Prioritise filters
         $filters = [
-            FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE,
-            FILTER_FLAG_NO_PRIV_RANGE,
-            null
+            Ip::ALL_ONLY_PUBLIC,
+            Ip::ALL_NO_PRIVATE,
+            Ip::ALL
         ];
         foreach ($filters as $filter) {
             // Find best IP
             foreach ($ips as $ip) {
-                if (filter_var($ip, FILTER_VALIDATE_IP, $filter ?? 0)) {
+                if (ConstraintValidator::validate($ip, [new Ip(version: $filter), new NotBlank()])->isValid()) {
                     return $ip;
                 }
             }
diff --git a/src/Core/Convert.php b/src/Core/Convert.php
index 4347014e8..ad8bc9500 100644
--- a/src/Core/Convert.php
+++ b/src/Core/Convert.php
@@ -2,9 +2,12 @@
 
 namespace SilverStripe\Core;
 
+use SilverStripe\Core\Validation\ConstraintValidator;
 use SimpleXMLElement;
 use SilverStripe\ORM\DB;
 use SilverStripe\View\Parsers\URLSegmentFilter;
+use Symfony\Component\Validator\Constraints\NotBlank;
+use Symfony\Component\Validator\Constraints\Url;
 
 /**
  * Library of conversion functions, implemented as static methods.
@@ -226,16 +229,14 @@ class Convert
 
     /**
      * Create a link if the string is a valid URL
-     *
-     * @param string $string The string to linkify
-     * @return string A link to the URL if string is a URL
      */
-    public static function linkIfMatch($string)
-    {
-        if (preg_match('/^[a-z+]+\:\/\/[a-zA-Z0-9$-_.+?&=!*\'()%]+$/', $string ?? '')) {
+    public static function linkIfMatch(
+        string $string,
+        array $protocols = ['file', 'ftp', 'http', 'https', 'imap', 'nntp']
+    ): string {
+        if (ConstraintValidator::validate($string, [new Url(protocols: $protocols), new NotBlank()])->isValid()) {
             return "<a style=\"white-space: nowrap\" href=\"$string\">$string</a>";
         }
-
         return $string;
     }
 
diff --git a/src/Forms/ConfirmedPasswordField.php b/src/Forms/ConfirmedPasswordField.php
index fa61dc91a..1856a057e 100644
--- a/src/Forms/ConfirmedPasswordField.php
+++ b/src/Forms/ConfirmedPasswordField.php
@@ -10,6 +10,8 @@ use SilverStripe\Security\Authenticator;
 use SilverStripe\Security\Security;
 use SilverStripe\View\HTML;
 use Closure;
+use SilverStripe\Core\Validation\ConstraintValidator;
+use Symfony\Component\Validator\Constraints\PasswordStrength;
 
 /**
  * Two masked input fields, checks for matching passwords.
@@ -25,34 +27,33 @@ class ConfirmedPasswordField extends FormField
 
     /**
      * Minimum character length of the password.
-     *
-     * @var int
      */
-    public $minLength = null;
+    public int $minLength = 0;
 
     /**
      * Maximum character length of the password.
-     *
-     * @var int
+     * 0 means no maximum length.
      */
-    public $maxLength = null;
+    public int $maxLength = 0;
 
     /**
-     * Enforces at least one digit and one alphanumeric
-     * character (in addition to {$minLength} and {$maxLength}
-     *
-     * @var boolean
+     * Enforces password strength validation based on entropy.
+     * See setMinPasswordStrength()
      */
-    public $requireStrongPassword = false;
+    public bool $requireStrongPassword = false;
 
     /**
      * Allow empty fields when entering the password for the first time
      * If this is set to true then a random password may be generated if the field is empty
      * depending on the value of $ConfirmedPasswordField::generateRandomPasswordOnEmtpy
-     *
-     * @var boolean
      */
-    public $canBeEmpty = false;
+    public bool $canBeEmpty = false;
+
+    /**
+     * Minimum password strength if requireStrongPassword is true
+     * See https://symfony.com/doc/current/reference/constraints/PasswordStrength.html#minscore
+     */
+    private int $minPasswordStrength = PasswordStrength::STRENGTH_STRONG;
 
     /**
      * Callback used to generate a random password if $this->canBeEmpty is true and the field is left blank
@@ -72,79 +73,54 @@ class ConfirmedPasswordField extends FormField
      *
      * Caution: The form field does not include any JavaScript or CSS when used outside of the CMS context,
      * since the required frontend dependencies are included through CMS bundling.
-     *
-     * @param boolean $showOnClick
      */
-    protected $showOnClick = false;
+    protected bool $showOnClick = false;
 
     /**
      * Check if the existing password should be entered first
-     *
-     * @var bool
      */
-    protected $requireExistingPassword = false;
+    protected bool $requireExistingPassword = false;
 
 
     /**
      * A place to temporarily store the confirm password value
-     *
-     * @var string
      */
-    protected $confirmValue;
+    protected ?string $confirmValue = null;
 
     /**
      * Store value of "Current Password" field
-     *
-     * @var string
      */
-    protected $currentPasswordValue;
+    protected ?string $currentPasswordValue = null;
 
     /**
      * Title for the link that triggers the visibility of password fields.
-     *
-     * @var string
      */
-    public $showOnClickTitle;
+    public string $showOnClickTitle = '';
 
     /**
      * Child fields (_Password, _ConfirmPassword)
-     *
-     * @var FieldList
      */
-    public $children;
+    public FieldList $children;
 
     protected $schemaDataType = FormField::SCHEMA_DATA_TYPE_STRUCTURAL;
 
-    /**
-     * @var PasswordField
-     */
-    protected $passwordField = null;
+    protected ?PasswordField $passwordField;
+
+    protected ?PasswordField $confirmPasswordfield;
+
+    protected ?HiddenField $hiddenField = null;
 
     /**
-     * @var PasswordField
-     */
-    protected $confirmPasswordfield = null;
-
-    /**
-     * @var HiddenField
-     */
-    protected $hiddenField = null;
-
-    /**
-     * @param string $name
-     * @param string $title
-     * @param mixed $value
      * @param Form $form Ignored for ConfirmedPasswordField.
-     * @param boolean $showOnClick
      * @param string $titleConfirmField Alternate title (not localizeable)
      */
     public function __construct(
-        $name,
-        $title = null,
-        $value = "",
-        $form = null,
-        $showOnClick = false,
-        $titleConfirmField = null
+        string $name,
+        ?string $title = null,
+        mixed $value = "",
+        ?Form $form = null,
+        bool $showOnClick = false,
+        ?string $titleConfirmField = null
     ) {
 
         // Set field title
@@ -528,14 +504,18 @@ class ConfirmedPasswordField extends FormField
         }
 
         if ($this->getRequireStrongPassword()) {
-            if (!preg_match('/^(([a-zA-Z]+\d+)|(\d+[a-zA-Z]+))[a-zA-Z0-9]*$/', $value ?? '')) {
+            $strongEnough = ConstraintValidator::validate(
+                $value,
+                new PasswordStrength(minScore: $this->getMinPasswordStrength())
+            )->isValid();
+            if (!$strongEnough) {
                 $validator->validationError(
                     $name,
                     _t(
-                        'SilverStripe\\Forms\\Form.VALIDATIONSTRONGPASSWORD',
-                        'Passwords must have at least one digit and one alphanumeric character'
+                        __CLASS__ . '.VALIDATIONSTRONGPASSWORD',
+                        'The password strength is too low. Please use a stronger password.'
                     ),
-                    "validation"
+                    'validation'
                 );
 
                 return $this->extendValidationResult(false, $validator);
@@ -637,24 +617,21 @@ class ConfirmedPasswordField extends FormField
 
     /**
      * Check if existing password is required
-     *
-     * @return bool
+     * If true, an extra form field will be added to enter the existing password
      */
-    public function getRequireExistingPassword()
+    public function getRequireExistingPassword(): bool
     {
         return $this->requireExistingPassword;
     }
 
     /**
      * Set if the existing password should be required
-     *
-     * @param bool $show Flag to show or hide this field
-     * @return $this
+     * If true, an extra form field will be added to enter the existing password
      */
-    public function setRequireExistingPassword($show)
+    public function setRequireExistingPassword(bool $show): static
     {
         // Don't modify if already added / removed
-        if ((bool)$show === $this->requireExistingPassword) {
+        if ($show === $this->requireExistingPassword) {
             return $this;
         }
         $this->requireExistingPassword = $show;
@@ -670,79 +647,91 @@ class ConfirmedPasswordField extends FormField
     }
 
     /**
-     * @return PasswordField
+     * Get the FormField that represents the main password field
      */
-    public function getPasswordField()
+    public function getPasswordField(): PasswordField
     {
         return $this->passwordField;
     }
 
     /**
-     * @return PasswordField
+     * Get the FormField that represents the "confirm" password field
      */
-    public function getConfirmPasswordField()
+    public function getConfirmPasswordField(): PasswordField
     {
         return $this->confirmPasswordfield;
     }
 
     /**
      * Set the minimum length required for passwords
-     *
-     * @param int $minLength
-     * @return $this
      */
-    public function setMinLength($minLength)
+    public function setMinLength(int $minLength): static
     {
-        $this->minLength = (int) $minLength;
+        $this->minLength = $minLength;
         return $this;
     }
 
     /**
-     * @return int
+     * Get the minimum length required for passwords
      */
-    public function getMinLength()
+    public function getMinLength(): int
     {
         return $this->minLength;
     }
 
     /**
-     * Set the maximum length required for passwords
-     *
-     * @param int $maxLength
-     * @return $this
+     * Set the maximum length required for passwords.
+     * 0 means no max length.
      */
-    public function setMaxLength($maxLength)
+    public function setMaxLength(int $maxLength): static
     {
-        $this->maxLength = (int) $maxLength;
+        $this->maxLength = $maxLength;
         return $this;
     }
 
     /**
-     * @return int
+     * Get the maximum length required for passwords.
+     * 0 means no max length.
      */
-    public function getMaxLength()
+    public function getMaxLength(): int
     {
         return $this->maxLength;
     }
 
     /**
-     * @param bool $requireStrongPassword
-     * @return $this
+     * Set whether password strength validation is enforced.
+     * See setMinPasswordStrength()
      */
-    public function setRequireStrongPassword($requireStrongPassword)
+    public function setRequireStrongPassword($requireStrongPassword): static
     {
         $this->requireStrongPassword = (bool) $requireStrongPassword;
         return $this;
     }
 
     /**
-     * @return bool
+     * Get whether password strength validation is enforced.
+     * See setMinPasswordStrength()
      */
-    public function getRequireStrongPassword()
+    public function getRequireStrongPassword(): bool
     {
         return $this->requireStrongPassword;
     }
 
+    /**
+     * Set minimum password strength. Only applies if requireStrongPassword is true
+     * See https://symfony.com/doc/current/reference/constraints/PasswordStrength.html#minscore
+     */
+    public function setMinPasswordStrength(int $strength): static
+    {
+        $this->minPasswordStrength = $strength;
+        return $this;
+    }
+
+    public function getMinPasswordStrength(): int
+    {
+        return $this->minPasswordStrength;
+    }
+
     /**
      * Appends a warning to the right title, or removes that appended warning.
      */
diff --git a/src/Forms/EmailField.php b/src/Forms/EmailField.php
index 68ea66d41..4426d67f8 100644
--- a/src/Forms/EmailField.php
+++ b/src/Forms/EmailField.php
@@ -2,52 +2,40 @@
 
 namespace SilverStripe\Forms;
 
+use SilverStripe\Core\Validation\ConstraintValidator;
+use Symfony\Component\Validator\Constraints\Email as EmailConstraint;
+
 /**
- * Text input field with validation for correct email format according to RFC 2822.
+ * Text input field with validation for correct email format according to the relevant RFC.
  */
 class EmailField extends TextField
 {
-
     protected $inputType = 'email';
-    /**
-     * {@inheritdoc}
-     */
+
     public function Type()
     {
         return 'email text';
     }
 
     /**
-     * Validates for RFC 2822 compliant email addresses.
-     *
-     * @see http://www.regular-expressions.info/email.html
-     * @see http://www.ietf.org/rfc/rfc2822.txt
+     * Validates for RFC compliant email addresses.
      *
      * @param Validator $validator
-     *
-     * @return string
      */
     public function validate($validator)
     {
-        $result = true;
         $this->value = trim($this->value ?? '');
 
-        $pattern = '^[a-z0-9!#$%&\'*+/=?^_`{|}~-]+(?:\\.[a-z0-9!#$%&\'*+/=?^_`{|}~-]+)*@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?$';
+        $message = _t('SilverStripe\\Forms\\EmailField.VALIDATION', 'Please enter an email address');
+        $result = ConstraintValidator::validate(
+            $this->value,
+            new EmailConstraint(message: $message, mode: EmailConstraint::VALIDATION_MODE_STRICT),
+            $this->getName()
+        );
+        $validator->getResult()->combineAnd($result);
+        $isValid = $result->isValid();
 
-        // Escape delimiter characters.
-        $safePattern = str_replace('/', '\\/', $pattern ?? '');
-
-        if ($this->value && !preg_match('/' . $safePattern . '/i', $this->value ?? '')) {
-            $validator->validationError(
-                $this->name,
-                _t('SilverStripe\\Forms\\EmailField.VALIDATION', 'Please enter an email address'),
-                'validation'
-            );
-
-            $result = false;
-        }
-
-        return $this->extendValidationResult($result, $validator);
+        return $this->extendValidationResult($isValid, $validator);
     }
 
     public function getSchemaValidation()
diff --git a/src/Forms/UrlField.php b/src/Forms/UrlField.php
index a8332d87a..4d5493fc6 100644
--- a/src/Forms/UrlField.php
+++ b/src/Forms/UrlField.php
@@ -7,10 +7,24 @@ use Symfony\Component\Validator\Constraints\Url;
 
 /**
  * Text input field with validation for a url
- * Url must include a scheme, either http:// or https://
+ * Url must include a protocol (aka scheme) such as https:// or http://
  */
 class UrlField extends TextField
 {
+    /**
+     * The default set of protocols allowed for valid URLs
+     */
+    private static array $default_protocols = ['https', 'http'];
+
+    /**
+     * The default value for whether a relative protocol (// on its own) is allowed
+     */
+    private static bool $default_allow_relative_protocol = false;
+
+    private array $protocols = [];
+
+    private ?bool $allowRelativeProtocol = null;
+
     public function Type()
     {
         return 'text url';
@@ -18,15 +32,64 @@ class UrlField extends TextField
 
     public function validate($validator)
     {
-        $result = true;
-        if ($this->value && !ConstraintValidator::validate($this->value, new Url())->isValid()) {
-            $validator->validationError(
-                $this->name,
-                _t(__CLASS__ . '.INVALID', 'Please enter a valid URL'),
-                'validation'
-            );
-            $result = false;
+        $allowedProtocols = $this->getAllowedProtocols();
+        $message = _t(
+            __CLASS__ . '.INVALID_WITH_PROTOCOL',
+            'Please enter a valid URL including a protocol, e.g {protocol}://example.com',
+            ['protocol' => $allowedProtocols[0]]
+        );
+        $result = ConstraintValidator::validate(
+            $this->value,
+            new Url(
+                message: $message,
+                protocols: $allowedProtocols,
+                relativeProtocol: $this->getAllowRelativeProtocol()
+            ),
+            $this->getName()
+        );
+        $validator->getResult()->combineAnd($result);
+        $isValid = $result->isValid();
+        return $this->extendValidationResult($isValid, $validator);
+    }
+
+    /**
+     * Set which protocols valid URLs are allowed to have
+     */
+    public function setAllowedProtocols(array $protocols): static
+    {
+        // Ensure the array isn't associative so we can use 0 index in validate().
+        $this->protocols = array_keys($protocols);
+        return $this;
+    }
+
+    /**
+     * Get which protocols valid URLs are allowed to have
+     */
+    public function getAllowedProtocols(): array
+    {
+        if (empty($this->protocols)) {
+            return static::config()->get('default_protocols');
         }
-        return $this->extendValidationResult($result, $validator);
+        return $this->protocols;
+    }
+
+    /**
+     * Set whether a relative protocol (// on its own) is allowed
+     */
+    public function setAllowRelativeProtocol(?bool $allow): static
+    {
+        $this->allowRelativeProtocol = $allow;
+        return $this;
+    }
+
+    /**
+     * Get whether a relative protocol (// on its own) is allowed
+     */
+    public function getAllowRelativeProtocol(): bool
+    {
+        if ($this->allowRelativeProtocol === null) {
+            return static::config()->get('default_allow_relative_protocol');
+        }
+        return $this->allowRelativeProtocol;
     }
 }
diff --git a/src/Security/Member.php b/src/Security/Member.php
index cfcee6b78..e5d198650 100644
--- a/src/Security/Member.php
+++ b/src/Security/Member.php
@@ -45,7 +45,8 @@ use SilverStripe\Forms\FormField;
 use SilverStripe\Forms\SearchableDropdownField;
 use SilverStripe\Forms\SearchableMultiDropdownField;
 use SilverStripe\ORM\FieldType\DBForeignKey;
-use SilverStripe\Dev\Deprecation;
+use SilverStripe\Security\Validation\PasswordValidator;
+use SilverStripe\Security\Validation\RulesPasswordValidator;
 
 /**
  * The member class which represents the users of the system
@@ -380,10 +381,8 @@ class Member extends DataObject
 
     /**
      * Set a {@link PasswordValidator} object to use to validate member's passwords.
-     *
-     * @param PasswordValidator $validator
      */
-    public static function set_password_validator(PasswordValidator $validator = null)
+    public static function set_password_validator(?PasswordValidator $validator = null)
     {
         // Override existing config
         Config::modify()->remove(Injector::class, PasswordValidator::class);
@@ -396,13 +395,11 @@ class Member extends DataObject
 
     /**
      * Returns the default {@link PasswordValidator}
-     *
-     * @return PasswordValidator|null
      */
-    public static function password_validator()
+    public static function password_validator(): ?PasswordValidator
     {
         if (Injector::inst()->has(PasswordValidator::class)) {
-            return Deprecation::withSuppressedNotice(fn() => Injector::inst()->get(PasswordValidator::class));
+            return Injector::inst()->get(PasswordValidator::class);
         }
         return null;
     }
@@ -1779,11 +1776,16 @@ class Member extends DataObject
     {
         $password = '';
         $validator = Member::password_validator();
-        if ($length && $validator && $length < $validator->getMinLength()) {
-            throw new InvalidArgumentException('length argument is less than password validator minLength');
+        if ($validator instanceof RulesPasswordValidator) {
+            $validatorMinLength = $validator->getMinLength();
+            if ($length && $length < $validatorMinLength) {
+                throw new InvalidArgumentException('length argument is less than password validator minLength');
+            }
+        } else {
+            // Make sure the password is long enough to beat even very strict entropy tests
+            $validatorMinLength = 128;
         }
-        $validatorMinLength = $validator ? $validator->getMinLength() : 0;
-        $len = $length ?: max($validatorMinLength, 20);
+        $len = max($length, $validatorMinLength, 20);
         // The default PasswordValidator checks the password includes the following four character sets
         $charsets = [
             'abcdefghijklmnopqrstuvwyxz',
diff --git a/src/Security/Validation/EntropyPasswordValidator.php b/src/Security/Validation/EntropyPasswordValidator.php
new file mode 100644
index 000000000..27c7f6186
--- /dev/null
+++ b/src/Security/Validation/EntropyPasswordValidator.php
@@ -0,0 +1,33 @@
+<?php
+
+namespace SilverStripe\Security\Validation;
+
+use SilverStripe\Core\Extensible;
+use SilverStripe\Core\Validation\ConstraintValidator;
+use SilverStripe\Core\Validation\ValidationResult;
+use SilverStripe\Security\Member;
+use Symfony\Component\Validator\Constraints\NotBlank;
+use Symfony\Component\Validator\Constraints\PasswordStrength;
+
+/**
+ * Validates passwords based on entropy.
+ */
+class EntropyPasswordValidator extends PasswordValidator
+{
+    use Extensible;
+
+    /**
+     * The strength of a valid password.
+     * See https://symfony.com/doc/current/reference/constraints/PasswordStrength.html#minscore
+     */
+    private static int $password_strength = PasswordStrength::STRENGTH_STRONG;
+
+    public function validate(string $password, Member $member): ValidationResult
+    {
+        $minScore = static::config()->get('password_strength');
+        $result = ConstraintValidator::validate($password, [new PasswordStrength(minScore: $minScore), new NotBlank()]);
+        $result->combineAnd(parent::validate($password, $member));
+        $this->extend('updateValidatePassword', $password, $member, $result, $this);
+        return $result;
+    }
+}
diff --git a/src/Security/Validation/PasswordValidator.php b/src/Security/Validation/PasswordValidator.php
new file mode 100644
index 000000000..fe0d83e2e
--- /dev/null
+++ b/src/Security/Validation/PasswordValidator.php
@@ -0,0 +1,72 @@
+<?php
+
+namespace SilverStripe\Security\Validation;
+
+use SilverStripe\Core\Config\Configurable;
+use SilverStripe\Core\Injector\Injectable;
+use SilverStripe\ORM\DataObject;
+use SilverStripe\Core\Validation\ValidationResult;
+use SilverStripe\Security\Member;
+use SilverStripe\Security\MemberPassword;
+
+/**
+ * Abstract validator with functionality for checking for reusing old passwords.
+ */
+abstract class PasswordValidator
+{
+    use Injectable;
+    use Configurable;
+
+    /**
+     * Default number of previous passwords to check for a reusing old passwords.
+     */
+    private static int $historic_count = 6;
+
+    protected ?int $historicalPasswordCount = null;
+
+    public function validate(string $password, Member $member): ValidationResult
+    {
+        $result = ValidationResult::create();
+
+        $historicCount = $this->getHistoricCount();
+        if ($historicCount) {
+            $idColumn = DataObject::getSchema()->sqlColumnForField(MemberPassword::class, 'MemberID');
+            $previousPasswords = MemberPassword::get()
+                ->where([$idColumn => $member->ID])
+                ->sort(['Created' => 'DESC', 'ID' => 'DESC'])
+                ->limit($historicCount);
+            foreach ($previousPasswords as $previousPassword) {
+                if ($previousPassword->checkPassword($password)) {
+                    $error = _t(
+                        PasswordValidator::class . '.PREVPASSWORD',
+                        'You\'ve already used that password in the past, please choose a new password'
+                    );
+                    $result->addError($error, 'bad', 'PREVIOUS_PASSWORD');
+                    break;
+                }
+            }
+        }
+
+        return $result;
+    }
+
+    /**
+     * Get the number of previous passwords to check for a reusing old passwords.
+     */
+    public function getHistoricCount(): int
+    {
+        if ($this->historicalPasswordCount !== null) {
+            return $this->historicalPasswordCount;
+        }
+        return $this->config()->get('historic_count') ?? 0;
+    }
+
+    /**
+     * Set the number of previous passwords to check for a reusing old passwords.
+     */
+    public function setHistoricCount(int $count): static
+    {
+        $this->historicalPasswordCount = $count;
+        return $this;
+    }
+}
diff --git a/src/Security/PasswordValidator.php b/src/Security/Validation/RulesPasswordValidator.php
similarity index 51%
rename from src/Security/PasswordValidator.php
rename to src/Security/Validation/RulesPasswordValidator.php
index 388e76fe6..27b44619b 100644
--- a/src/Security/PasswordValidator.php
+++ b/src/Security/Validation/RulesPasswordValidator.php
@@ -1,39 +1,32 @@
 <?php
 
-namespace SilverStripe\Security;
+namespace SilverStripe\Security\Validation;
 
-use SilverStripe\Core\Config\Configurable;
 use SilverStripe\Core\Extensible;
-use SilverStripe\Core\Injector\Injectable;
 use SilverStripe\Core\Validation\ValidationResult;
-use SilverStripe\Dev\Deprecation;
+use SilverStripe\Security\Member;
 
 /**
- * This class represents a validator for member passwords.
+ * Validates passwords based on a set of regex rules about what the password must contain.
  *
  * <code>
  * $pwdVal = new PasswordValidator();
  * $pwdValidator->setMinLength(7);
- * $pwdValidator->checkHistoricalPasswords(6);
+ * $pwdValidator->setHistoricCount(6);
  * $pwdValidator->setMinTestScore(3);
  * $pwdValidator->setTestNames(array("lowercase", "uppercase", "digits", "punctuation"));
  *
  * Member::set_password_validator($pwdValidator);
  * </code>
- *
- * @deprecated 5.4.0 Will be renamed to SilverStripe\Security\Validation\RulesPasswordValidator
  */
-class PasswordValidator
+class RulesPasswordValidator extends PasswordValidator
 {
-    use Injectable;
-    use Configurable;
     use Extensible;
 
     /**
-     * @config
-     * @var array
+     * Regex to test the password against. See min_test_score.
      */
-    private static $character_strength_tests = [
+    private static array $character_strength_tests = [
         'lowercase' => '/[a-z]/',
         'uppercase' => '/[A-Z]/',
         'digits' => '/[0-9]/',
@@ -41,89 +34,62 @@ class PasswordValidator
     ];
 
     /**
-     * @config
-     * @var int
+     * Default minimum number of characters for a valid password.
      */
-    private static $min_length = null;
+    private static int $min_length = 8;
 
     /**
-     * @config
-     * @var int
+     * Default minimum test score for a valid password.
+     * The test score is the number of character_strength_tests that the password matches.
      */
-    private static $min_test_score = null;
+    private static int $min_test_score = 0;
 
-    /**
-     * @config
-     * @var int
-     */
-    private static $historic_count = null;
+    protected ?int $minLength = null;
 
-    /**
-     * @var int
-     */
-    protected $minLength = null;
-
-    /**
-     * @var int
-     */
-    protected $minScore = null;
+    protected ?int $minScore = null;
 
     /**
      * @var string[]
      */
-    protected $testNames = null;
+    protected ?array $testNames = null;
 
     /**
-     * @var int
+     * Get the minimum number of characters for a valid password.
      */
-    protected $historicalPasswordCount = null;
-
-    public function __construct()
-    {
-        Deprecation::notice(
-            '5.4.0',
-            'Will be renamed to SilverStripe\Security\Validation\RulesPasswordValidator',
-            Deprecation::SCOPE_CLASS
-        );
-    }
-
-    /**
-     * @return int
-     */
-    public function getMinLength()
+    public function getMinLength(): int
     {
         if ($this->minLength !== null) {
             return $this->minLength;
         }
-        return $this->config()->get('min_length');
+        return $this->config()->get('min_length') ?? 0;
     }
 
     /**
-     * @param int $minLength
-     * @return $this
+     * Set the minimum number of characters for a valid password.
      */
-    public function setMinLength($minLength)
+    public function setMinLength(int $minLength): static
     {
         $this->minLength = $minLength;
         return $this;
     }
 
     /**
-     * @return integer
+     * Get the minimum test score for a valid password.
+     * The test score is the number of character_strength_tests that the password matches.
      */
-    public function getMinTestScore()
+    public function getMinTestScore(): int
     {
         if ($this->minScore !== null) {
             return $this->minScore;
         }
-        return $this->config()->get('min_test_score');
+        return $this->config()->get('min_test_score') ?? 0;
     }
 
     /**
-     * @param int $minScore
-     * @return $this
+     * Set the minimum test score for a valid password.
+     * The test score is the number of character_strength_tests that the password matches.
      */
-    public function setMinTestScore($minScore)
+    public function setMinTestScore(int $minScore): static
     {
         $this->minScore = $minScore;
         return $this;
@@ -134,7 +100,7 @@ class PasswordValidator
      *
      * @return string[]
      */
-    public function getTestNames()
+    public function getTestNames(): array
     {
         if ($this->testNames !== null) {
             return $this->testNames;
@@ -146,51 +112,22 @@ class PasswordValidator
      * Set list of tests to use for this validator
      *
      * @param string[] $testNames
-     * @return $this
      */
-    public function setTestNames($testNames)
+    public function setTestNames(array $testNames): static
     {
         $this->testNames = $testNames;
         return $this;
     }
 
-    /**
-     * @return int
-     */
-    public function getHistoricCount()
-    {
-        if ($this->historicalPasswordCount !== null) {
-            return $this->historicalPasswordCount;
-        }
-        return $this->config()->get('historic_count');
-    }
-
-    /**
-     * @param int $count
-     * @return $this
-     */
-    public function setHistoricCount($count)
-    {
-        $this->historicalPasswordCount = $count;
-        return $this;
-    }
-
     /**
      * Gets all possible tests
-     *
-     * @return array
      */
-    public function getTests()
+    public function getTests(): array
     {
         return $this->config()->get('character_strength_tests');
     }
 
-    /**
-     * @param string $password
-     * @param Member $member
-     * @return ValidationResult
-     */
-    public function validate($password, $member)
+    public function validate(string $password, Member $member): ValidationResult
     {
         $valid = ValidationResult::create();
 
@@ -234,23 +171,7 @@ class PasswordValidator
             }
         }
 
-        $historicCount = $this->getHistoricCount();
-        if ($historicCount) {
-            $previousPasswords = MemberPassword::get()
-                ->where(['"MemberPassword"."MemberID"' => $member->ID])
-                ->sort('"Created" DESC, "ID" DESC')
-                ->limit($historicCount);
-            foreach ($previousPasswords as $previousPassword) {
-                if ($previousPassword->checkPassword($password)) {
-                    $error = _t(
-                        __CLASS__ . '.PREVPASSWORD',
-                        'You\'ve already used that password in the past, please choose a new password'
-                    );
-                    $valid->addError($error, 'bad', 'PREVIOUS_PASSWORD');
-                    break;
-                }
-            }
-        }
+        $valid->combineAnd(parent::validate($password, $member));
 
         $this->extend('updateValidatePassword', $password, $member, $valid, $this);
 
diff --git a/tests/php/Forms/ConfirmedPasswordFieldTest.php b/tests/php/Forms/ConfirmedPasswordFieldTest.php
index db2aed705..164cdf575 100644
--- a/tests/php/Forms/ConfirmedPasswordFieldTest.php
+++ b/tests/php/Forms/ConfirmedPasswordFieldTest.php
@@ -11,11 +11,9 @@ use SilverStripe\Forms\Form;
 use SilverStripe\Forms\ReadonlyField;
 use SilverStripe\Forms\RequiredFields;
 use SilverStripe\Security\Member;
-use SilverStripe\Security\PasswordValidator;
 use SilverStripe\View\SSViewer;
 use Closure;
 use PHPUnit\Framework\Attributes\DataProvider;
-use SilverStripe\Dev\Deprecation;
 
 class ConfirmedPasswordFieldTest extends SapphireTest
 {
@@ -25,11 +23,7 @@ class ConfirmedPasswordFieldTest extends SapphireTest
     {
         parent::setUp();
 
-        Deprecation::withSuppressedNotice(
-            fn() => PasswordValidator::singleton()
-            ->setMinLength(0)
-            ->setTestNames([])
-        );
+        Member::set_password_validator(null);
     }
 
     public function testSetValue()
@@ -217,10 +211,10 @@ class ConfirmedPasswordFieldTest extends SapphireTest
         return [
             'valid: within min and max' => [3, 8, true],
             'invalid: lower than min with max' => [8, 12, false, 'Passwords must be 8 to 12 characters long'],
-            'valid: greater than min' => [3, null, true],
-            'invalid: lower than min' => [8, null, false, 'Passwords must be at least 8 characters long'],
-            'valid: less than max' => [null, 8, true],
-            'invalid: greater than max' => [null, 4, false, 'Passwords must be at most 4 characters long'],
+            'valid: greater than min' => [3, 0, true],
+            'invalid: lower than min' => [8, 0, false, 'Passwords must be at least 8 characters long'],
+            'valid: less than max' => [0, 8, true],
+            'invalid: greater than max' => [0, 4, false, 'Passwords must be at most 4 characters long'],
 
         ];
     }
@@ -239,7 +233,7 @@ class ConfirmedPasswordFieldTest extends SapphireTest
         $this->assertFalse($result, 'Validate method should return its result');
         $this->assertFalse($validator->getResult()->isValid());
         $this->assertStringContainsString(
-            'Passwords must have at least one digit and one alphanumeric character',
+            'The password strength is too low. Please use a stronger password.',
             json_encode($validator->getResult()->__serialize())
         );
     }
diff --git a/tests/php/Forms/EmailFieldTest.php b/tests/php/Forms/EmailFieldTest.php
index 26723e555..a3a054f4e 100644
--- a/tests/php/Forms/EmailFieldTest.php
+++ b/tests/php/Forms/EmailFieldTest.php
@@ -4,9 +4,7 @@ namespace SilverStripe\Forms\Tests;
 
 use SilverStripe\Dev\FunctionalTest;
 use SilverStripe\Forms\EmailField;
-use Exception;
-use PHPUnit\Framework\AssertionFailedError;
-use SilverStripe\Forms\Tests\EmailFieldTest\TestValidator;
+use SilverStripe\Forms\FieldsValidator;
 
 class EmailFieldTest extends FunctionalTest
 {
@@ -40,21 +38,14 @@ class EmailFieldTest extends FunctionalTest
         $field = new EmailField("MyEmail");
         $field->setValue($email);
 
-        $val = new TestValidator();
-        try {
-            $field->validate($val);
-            // If we expect failure and processing gets here without an exception, the test failed
-            $this->assertTrue($expectSuccess, $checkText . " (/$email/ passed validation, but not expected to)");
-        } catch (Exception $e) {
-            if ($e instanceof AssertionFailedError) {
-                 // re-throw assertion failure
-                throw $e;
-            } elseif ($expectSuccess) {
-                $this->fail(
-                    $checkText . ": " . $e->getMessage() . " (/$email/ did not pass validation, but was expected to)"
-                );
-            }
+        if ($expectSuccess) {
+            $message = $checkText . " (/$email/ did not pass validation, but was expected to)";
+        } else {
+            $message = $checkText . " (/$email/ passed validation, but not expected to)";
         }
+
+        $result = $field->validate(new FieldsValidator());
+        $this->assertSame($expectSuccess, $result, $message);
     }
 
     /**
diff --git a/tests/php/Forms/EmailFieldTest/TestValidator.php b/tests/php/Forms/EmailFieldTest/TestValidator.php
deleted file mode 100644
index 21e00a989..000000000
--- a/tests/php/Forms/EmailFieldTest/TestValidator.php
+++ /dev/null
@@ -1,27 +0,0 @@
-<?php
-
-namespace SilverStripe\Forms\Tests\EmailFieldTest;
-
-use Exception;
-use SilverStripe\Forms\Validator;
-use SilverStripe\Core\Validation\ValidationResult;
-
-class TestValidator extends Validator
-{
-    public function validationError(
-        $fieldName,
-        $message,
-        $messageType = ValidationResult::TYPE_ERROR,
-        $cast = ValidationResult::CAST_TEXT
-    ) {
-        throw new Exception($message);
-    }
-
-    public function javascript()
-    {
-    }
-
-    public function php($data)
-    {
-    }
-}
diff --git a/tests/php/Security/MemberAuthenticatorTest.php b/tests/php/Security/MemberAuthenticatorTest.php
index 8b7b1e5ff..b785226ae 100644
--- a/tests/php/Security/MemberAuthenticatorTest.php
+++ b/tests/php/Security/MemberAuthenticatorTest.php
@@ -6,7 +6,6 @@ use SilverStripe\Control\Controller;
 use SilverStripe\Control\NullHTTPRequest;
 use SilverStripe\Core\Config\Config;
 use SilverStripe\Core\Injector\Injector;
-use SilverStripe\Dev\Deprecation;
 use SilverStripe\Dev\SapphireTest;
 use SilverStripe\ORM\FieldType\DBDatetime;
 use SilverStripe\Core\Validation\ValidationResult;
@@ -19,7 +18,6 @@ use SilverStripe\Security\MemberAuthenticator\CMSMemberAuthenticator;
 use SilverStripe\Security\MemberAuthenticator\CMSMemberLoginForm;
 use SilverStripe\Security\MemberAuthenticator\MemberAuthenticator;
 use SilverStripe\Security\MemberAuthenticator\MemberLoginForm;
-use SilverStripe\Security\PasswordValidator;
 use SilverStripe\Security\Security;
 
 class MemberAuthenticatorTest extends SapphireTest
@@ -44,12 +42,8 @@ class MemberAuthenticatorTest extends SapphireTest
         }
         DefaultAdminService::setDefaultAdmin('admin', 'password');
 
-        // Enforce dummy validation (this can otherwise be influenced by recipe config)
-        Deprecation::withSuppressedNotice(
-            fn() => PasswordValidator::singleton()
-            ->setMinLength(0)
-            ->setTestNames([])
-        );
+        // Enforce no password validation
+        Member::set_password_validator(null);
     }
 
     protected function tearDown(): void
diff --git a/tests/php/Security/MemberCsvBulkLoaderTest.php b/tests/php/Security/MemberCsvBulkLoaderTest.php
index 6860ee18f..c9cefdee1 100644
--- a/tests/php/Security/MemberCsvBulkLoaderTest.php
+++ b/tests/php/Security/MemberCsvBulkLoaderTest.php
@@ -2,12 +2,10 @@
 
 namespace SilverStripe\Security\Tests;
 
-use SilverStripe\Dev\Deprecation;
 use SilverStripe\ORM\DataObject;
 use SilverStripe\Security\Group;
 use SilverStripe\Security\MemberCsvBulkLoader;
 use SilverStripe\Security\Member;
-use SilverStripe\Security\PasswordValidator;
 use SilverStripe\Security\Security;
 use SilverStripe\Dev\SapphireTest;
 use SilverStripe\Security\MemberAuthenticator\MemberAuthenticator;
@@ -19,12 +17,7 @@ class MemberCsvBulkLoaderTest extends SapphireTest
     protected function setUp(): void
     {
         parent::setUp();
-
-        Deprecation::withSuppressedNotice(
-            fn() => PasswordValidator::singleton()
-            ->setMinLength(0)
-            ->setTestNames([])
-        );
+        Member::set_password_validator(null);
     }
 
     public function testNewImport()
diff --git a/tests/php/Security/MemberTest.php b/tests/php/Security/MemberTest.php
index eb60dabe8..935fa90fc 100644
--- a/tests/php/Security/MemberTest.php
+++ b/tests/php/Security/MemberTest.php
@@ -8,7 +8,6 @@ use SilverStripe\Control\Cookie;
 use SilverStripe\Core\Config\Config;
 use SilverStripe\Core\Convert;
 use SilverStripe\Core\Injector\Injector;
-use SilverStripe\Dev\Deprecation;
 use SilverStripe\Dev\FunctionalTest;
 use SilverStripe\Forms\CheckboxField;
 use SilverStripe\Forms\FieldList;
@@ -29,7 +28,6 @@ use SilverStripe\Security\MemberAuthenticator\MemberAuthenticator;
 use SilverStripe\Security\MemberAuthenticator\SessionAuthenticationHandler;
 use SilverStripe\Security\MemberPassword;
 use SilverStripe\Security\PasswordEncryptor_Blowfish;
-use SilverStripe\Security\PasswordValidator;
 use SilverStripe\Security\Permission;
 use SilverStripe\Security\RememberLoginHash;
 use SilverStripe\Security\Security;
@@ -37,6 +35,8 @@ use SilverStripe\Security\Tests\MemberTest\FieldsExtension;
 use SilverStripe\SessionManager\Models\LoginSession;
 use ReflectionMethod;
 use PHPUnit\Framework\Attributes\DataProvider;
+use SilverStripe\Security\Validation\EntropyPasswordValidator;
+use SilverStripe\Security\Validation\RulesPasswordValidator;
 
 class MemberTest extends FunctionalTest
 {
@@ -75,12 +75,6 @@ class MemberTest extends FunctionalTest
 
         Member::config()->set('unique_identifier_field', 'Email');
 
-        Deprecation::withSuppressedNotice(
-            fn() => PasswordValidator::singleton()
-            ->setMinLength(0)
-            ->setTestNames([])
-        );
-
         i18n::set_locale('en_US');
     }
 
@@ -1743,7 +1737,7 @@ class MemberTest extends FunctionalTest
     public function testChangePasswordOnlyValidatesPlaintext()
     {
         // This validator requires passwords to be 17 characters long
-        Member::set_password_validator(Deprecation::withSuppressedNotice(fn() => new MemberTest\VerySpecificPasswordValidator()));
+        Member::set_password_validator(new MemberTest\VerySpecificPasswordValidator());
 
         // This algorithm will never return a 17 character hash
         Security::config()->set('password_encryption_algorithm', 'blowfish');
@@ -1770,11 +1764,23 @@ class MemberTest extends FunctionalTest
         $this->assertNotNull(Member::get()->find('Email', 'trimmed@test.com'));
     }
 
-    public function testChangePasswordToBlankIsValidated()
+    public static function provideChangePasswordToBlankIsValidated(): array
     {
-        Member::set_password_validator(Deprecation::withSuppressedNotice(fn() => new PasswordValidator()));
-        // override setup() function which setMinLength(0)
-        PasswordValidator::singleton()->setMinLength(8);
+        return [
+            [
+                'validatorClass' => RulesPasswordValidator::class,
+            ],
+            [
+                'validatorClass' => EntropyPasswordValidator::class,
+            ],
+        ];
+    }
+
+    #[DataProvider('provideChangePasswordToBlankIsValidated')]
+    public function testChangePasswordToBlankIsValidated(string $validatorClass): void
+    {
+        $validator = new $validatorClass();
+        Member::set_password_validator($validator);
         // 'test' member has a password defined in yml
         $member = $this->objFromFixture(Member::class, 'test');
         $result = $member->changePassword('');
@@ -1896,34 +1902,57 @@ class MemberTest extends FunctionalTest
         ];
     }
 
-    public function testGenerateRandomPassword()
+    public static function provideGenerateRandomPassword(): array
+    {
+        return [
+            [
+                'validatorClass' => RulesPasswordValidator::class,
+            ],
+            [
+                'validatorClass' => EntropyPasswordValidator::class,
+            ],
+        ];
+    }
+
+    #[DataProvider('provideGenerateRandomPassword')]
+    public function testGenerateRandomPassword(string $validatorClass): void
     {
         $member = new Member();
         // no password validator
         Member::set_password_validator(null);
-        // password length is same as length argument
+        // password length is min 128 chars long
         $password = $member->generateRandomPassword(5);
-        $this->assertSame(5, strlen($password));
-        // default to 20 if not length argument
-        $password = $member->generateRandomPassword();
-        $this->assertSame(20, strlen($password));
+        $this->assertSame(128, strlen($password));
+        // password length can be longer
+        $password = $member->generateRandomPassword(130);
+        $this->assertSame(130, strlen($password));
         // password validator
-        $validator = Deprecation::withSuppressedNotice(fn() => new PasswordValidator());
+        $validator = new $validatorClass();
         Member::set_password_validator($validator);
-        // Password length of 20 even if validator minLength is less than 20
-        $validator->setMinLength(10);
+        if ($validator instanceof RulesPasswordValidator) {
+            // Password length of 20 even if validator minLength is less than 20
+            $validator->setMinLength(10);
+            $minLengthInMember = 20;
+        } else {
+            $minLengthInMember = 128;
+        }
         $password = $member->generateRandomPassword();
-        $this->assertSame(20, strlen($password));
-        // Password length of 25 if passing length argument, and validator minlength is less than length argument
-        $password = $member->generateRandomPassword(25);
-        $this->assertSame(25, strlen($password));
-        // Password length is validator minLength if validator minLength is greater than 20 and no length argument
-        $validator->setMinLength(30);
-        $password = $member->generateRandomPassword();
-        $this->assertSame(30, strlen($password));
-        // Exception throw if length argument is less than validator minLength
-        $this->expectException(InvalidArgumentException::class);
-        $this->expectExceptionMessage('length argument is less than password validator minLength');
-        $password = $member->generateRandomPassword(15);
+        $this->assertSame($minLengthInMember, strlen($password));
+        // Password length of 256 if passing length argument, and validator minlength is less than length argument
+        $password = $member->generateRandomPassword(256);
+        $this->assertSame(256, strlen($password));
+        if ($validator instanceof RulesPasswordValidator) {
+            // Password length is validator minLength if validator minLength is greater than 20 and no length argument
+            $validator->setMinLength(30);
+            $password = $member->generateRandomPassword();
+            $this->assertSame(30, strlen($password));
+            // Exception throw if length argument is less than validator minLength
+            $this->expectException(InvalidArgumentException::class);
+            $this->expectExceptionMessage('length argument is less than password validator minLength');
+            $password = $member->generateRandomPassword(15);
+        } else {
+            // No exception for entropy validator
+            $password = $member->generateRandomPassword(15);
+        }
     }
 }
diff --git a/tests/php/Security/MemberTest/TestPasswordValidator.php b/tests/php/Security/MemberTest/TestPasswordValidator.php
index 834507f61..7ea86743e 100644
--- a/tests/php/Security/MemberTest/TestPasswordValidator.php
+++ b/tests/php/Security/MemberTest/TestPasswordValidator.php
@@ -3,9 +3,9 @@
 namespace SilverStripe\Security\Tests\MemberTest;
 
 use SilverStripe\Dev\TestOnly;
-use SilverStripe\Security\PasswordValidator;
+use SilverStripe\Security\Validation\RulesPasswordValidator;
 
-class TestPasswordValidator extends PasswordValidator implements TestOnly
+class TestPasswordValidator extends RulesPasswordValidator implements TestOnly
 {
     public function __construct()
     {
diff --git a/tests/php/Security/MemberTest/VerySpecificPasswordValidator.php b/tests/php/Security/MemberTest/VerySpecificPasswordValidator.php
index 28c66b5de..d37af6a07 100644
--- a/tests/php/Security/MemberTest/VerySpecificPasswordValidator.php
+++ b/tests/php/Security/MemberTest/VerySpecificPasswordValidator.php
@@ -4,11 +4,12 @@ namespace SilverStripe\Security\Tests\MemberTest;
 
 use SilverStripe\Dev\TestOnly;
 use SilverStripe\Core\Validation\ValidationResult;
-use SilverStripe\Security\PasswordValidator;
+use SilverStripe\Security\Member;
+use SilverStripe\Security\Validation\PasswordValidator;
 
 class VerySpecificPasswordValidator extends PasswordValidator implements TestOnly
 {
-    public function validate($password, $member)
+    public function validate(string $password, Member $member): ValidationResult
     {
         $result = ValidationResult::create();
         if (strlen($password ?? '') !== 17) {
diff --git a/tests/php/Security/SecurityTest.php b/tests/php/Security/SecurityTest.php
index 44573e00b..9f73a925d 100644
--- a/tests/php/Security/SecurityTest.php
+++ b/tests/php/Security/SecurityTest.php
@@ -22,7 +22,6 @@ use SilverStripe\Core\Validation\ValidationResult;
 use SilverStripe\Security\LoginAttempt;
 use SilverStripe\Security\Member;
 use SilverStripe\Security\MemberAuthenticator\MemberAuthenticator;
-use SilverStripe\Security\PasswordValidator;
 use SilverStripe\Security\Security;
 use SilverStripe\Security\SecurityToken;
 
@@ -60,11 +59,6 @@ class SecurityTest extends FunctionalTest
 
         Member::config()->set('unique_identifier_field', 'Email');
 
-        PasswordValidator::config()
-            ->remove('min_length')
-            ->remove('historic_count')
-            ->remove('min_test_score');
-
         Member::set_password_validator(null);
 
         parent::setUp();
diff --git a/tests/php/Security/Validation/EntropyPasswordValidatorTest.php b/tests/php/Security/Validation/EntropyPasswordValidatorTest.php
new file mode 100644
index 000000000..8e856665c
--- /dev/null
+++ b/tests/php/Security/Validation/EntropyPasswordValidatorTest.php
@@ -0,0 +1,42 @@
+<?php
+
+namespace SilverStripe\Security\Tests\Validation;
+
+use PHPUnit\Framework\Attributes\DataProvider;
+use SilverStripe\Dev\SapphireTest;
+use SilverStripe\Security\Member;
+use SilverStripe\Security\Validation\EntropyPasswordValidator;
+
+/**
+ * EntropyPasswordValidator uses a third-party for its validation so we don't need rigorous testing here.
+ * Just test that stupid simple passwords don't pass, and complex ones do.
+ */
+class EntropyPasswordValidatorTest extends SapphireTest
+{
+    protected $usesDatabase = false;
+
+    public static function provideValidate(): array
+    {
+        return [
+            [
+                'password' => '',
+                'expected' => false,
+            ],
+            [
+                'password' => 'password123',
+                'expected' => false,
+            ],
+            [
+                'password' => 'This is a really long and complex PASSWORD',
+                'expected' => true,
+            ],
+        ];
+    }
+
+    #[DataProvider('provideValidate')]
+    public function testValidate(string $password, bool $expected): void
+    {
+        $validator = new EntropyPasswordValidator();
+        $this->assertSame($expected, $validator->validate($password, new Member())->isValid());
+    }
+}
diff --git a/tests/php/Security/Validation/PasswordValidatorTest.php b/tests/php/Security/Validation/PasswordValidatorTest.php
new file mode 100644
index 000000000..c096db109
--- /dev/null
+++ b/tests/php/Security/Validation/PasswordValidatorTest.php
@@ -0,0 +1,40 @@
+<?php
+
+namespace SilverStripe\Security\Tests\Validation;
+
+use SilverStripe\Dev\SapphireTest;
+use SilverStripe\Security\Member;
+use SilverStripe\Security\Tests\Validation\RulesPasswordValidatorTest\DummyPasswordValidator;
+
+class PasswordValidatorTest extends SapphireTest
+{
+    /**
+     * {@inheritDoc}
+     * @var bool
+     */
+    protected $usesDatabase = true;
+
+    public function testValidate()
+    {
+        $validator = new DummyPasswordValidator;
+        $validator->setHistoricCount(3);
+        Member::set_password_validator($validator);
+
+        $member = new Member;
+        $member->FirstName = 'Repeat';
+        $member->Surname = 'Password-Man';
+        $member->Password = 'honk';
+        $member->write();
+
+        // Create a set of used passwords
+        $member->changePassword('foobar');
+        $member->changePassword('foobaz');
+        $member->changePassword('barbaz');
+
+        $this->assertFalse($member->changePassword('barbaz')->isValid());
+        $this->assertFalse($member->changePassword('foobaz')->isValid());
+        $this->assertFalse($member->changePassword('foobar')->isValid());
+        $this->assertTrue($member->changePassword('honk')->isValid());
+        $this->assertTrue($member->changePassword('newpassword')->isValid());
+    }
+}
diff --git a/tests/php/Security/Validation/PasswordValidatorTest/DummyPasswordValidator.php b/tests/php/Security/Validation/PasswordValidatorTest/DummyPasswordValidator.php
new file mode 100644
index 000000000..db066c24f
--- /dev/null
+++ b/tests/php/Security/Validation/PasswordValidatorTest/DummyPasswordValidator.php
@@ -0,0 +1,11 @@
+<?php
+
+namespace SilverStripe\Security\Tests\Validation\RulesPasswordValidatorTest;
+
+use SilverStripe\Dev\TestOnly;
+use SilverStripe\Security\Validation\PasswordValidator;
+
+class DummyPasswordValidator extends PasswordValidator implements TestOnly
+{
+    // no-op, just need a concrete class instead of an abstract one.
+}
diff --git a/tests/php/Security/PasswordValidatorTest.php b/tests/php/Security/Validation/RulesPasswordValidatorTest.php
similarity index 53%
rename from tests/php/Security/PasswordValidatorTest.php
rename to tests/php/Security/Validation/RulesPasswordValidatorTest.php
index 8b92eac94..b8af48f98 100644
--- a/tests/php/Security/PasswordValidatorTest.php
+++ b/tests/php/Security/Validation/RulesPasswordValidatorTest.php
@@ -1,25 +1,20 @@
 <?php
 
-namespace SilverStripe\Security\Tests;
+namespace SilverStripe\Security\Tests\Validation;
 
-use SilverStripe\Dev\Deprecation;
 use SilverStripe\Dev\SapphireTest;
 use SilverStripe\Security\Member;
-use SilverStripe\Security\PasswordValidator;
+use SilverStripe\Security\Validation\RulesPasswordValidator;
 
-class PasswordValidatorTest extends SapphireTest
+class RulesPasswordValidatorTest extends SapphireTest
 {
-    /**
-     * {@inheritDoc}
-     * @var bool
-     */
-    protected $usesDatabase = true;
+    protected $usesDatabase = false;
 
     protected function setUp(): void
     {
         parent::setUp();
 
-        PasswordValidator::config()
+        RulesPasswordValidator::config()
             ->remove('min_length')
             ->remove('historic_count')
             ->set('min_test_score', 0);
@@ -27,7 +22,7 @@ class PasswordValidatorTest extends SapphireTest
 
     public function testValidate()
     {
-        $v = Deprecation::withSuppressedNotice(fn() => new PasswordValidator());
+        $v = new RulesPasswordValidator();
         $r = $v->validate('', new Member());
         $this->assertTrue($r->isValid(), 'Empty password is valid by default');
 
@@ -37,7 +32,7 @@ class PasswordValidatorTest extends SapphireTest
 
     public function testValidateMinLength()
     {
-        $v = Deprecation::withSuppressedNotice(fn() => new PasswordValidator());
+        $v = new RulesPasswordValidator();
 
         $v->setMinLength(4);
         $r = $v->validate('123', new Member());
@@ -51,7 +46,7 @@ class PasswordValidatorTest extends SapphireTest
     public function testValidateMinScore()
     {
         // Set both score and set of tests
-        $v = Deprecation::withSuppressedNotice(fn() => new PasswordValidator());
+        $v = new RulesPasswordValidator();
         $v->setMinTestScore(3);
         $v->setTestNames(["lowercase", "uppercase", "digits", "punctuation"]);
 
@@ -62,7 +57,7 @@ class PasswordValidatorTest extends SapphireTest
         $this->assertTrue($r->isValid(), 'Passing enough tests');
 
         // Ensure min score without tests works (uses default tests)
-        $v = Deprecation::withSuppressedNotice(fn() => new PasswordValidator());
+        $v = new RulesPasswordValidator();
         $v->setMinTestScore(3);
 
         $r = $v->validate('aA', new Member());
@@ -76,31 +71,4 @@ class PasswordValidatorTest extends SapphireTest
         $r = $v->validate('aA1!', new Member());
         $this->assertTrue($r->isValid(), 'Passing enough tests');
     }
-
-    /**
-     * Test that a certain number of historical passwords are checked if specified
-     */
-    public function testHistoricalPasswordCount()
-    {
-        $validator = Deprecation::withSuppressedNotice(fn() => new PasswordValidator);
-        $validator->setHistoricCount(3);
-        Member::set_password_validator($validator);
-
-        $member = new Member;
-        $member->FirstName = 'Repeat';
-        $member->Surname = 'Password-Man';
-        $member->Password = 'honk';
-        $member->write();
-
-        // Create a set of used passwords
-        $member->changePassword('foobar');
-        $member->changePassword('foobaz');
-        $member->changePassword('barbaz');
-
-        $this->assertFalse($member->changePassword('barbaz')->isValid());
-        $this->assertFalse($member->changePassword('foobaz')->isValid());
-        $this->assertFalse($member->changePassword('foobar')->isValid());
-        $this->assertTrue($member->changePassword('honk')->isValid());
-        $this->assertTrue($member->changePassword('newpassword')->isValid());
-    }
 }
diff --git a/tests/php/Security/VersionedMemberAuthenticatorTest.php b/tests/php/Security/VersionedMemberAuthenticatorTest.php
index 7fd813b28..0a3dbb215 100644
--- a/tests/php/Security/VersionedMemberAuthenticatorTest.php
+++ b/tests/php/Security/VersionedMemberAuthenticatorTest.php
@@ -3,24 +3,11 @@
 namespace SilverStripe\Security\Tests;
 
 use SilverStripe\Control\Controller;
-use SilverStripe\Control\NullHTTPRequest;
-use SilverStripe\Core\Config\Config;
-use SilverStripe\Core\Injector\Injector;
-use SilverStripe\Dev\Deprecation;
 use SilverStripe\Dev\SapphireTest;
 use SilverStripe\ORM\FieldType\DBDatetime;
 use SilverStripe\Core\Validation\ValidationResult;
-use SilverStripe\Security\Authenticator;
-use SilverStripe\Security\DefaultAdminService;
-use SilverStripe\Security\IdentityStore;
-use SilverStripe\Security\LoginAttempt;
 use SilverStripe\Security\Member;
-use SilverStripe\Security\MemberAuthenticator\CMSMemberAuthenticator;
-use SilverStripe\Security\MemberAuthenticator\CMSMemberLoginForm;
 use SilverStripe\Security\MemberAuthenticator\MemberAuthenticator;
-use SilverStripe\Security\MemberAuthenticator\MemberLoginForm;
-use SilverStripe\Security\PasswordValidator;
-use SilverStripe\Security\Security;
 use SilverStripe\Versioned\Versioned;
 
 class VersionedMemberAuthenticatorTest extends SapphireTest
@@ -43,12 +30,8 @@ class VersionedMemberAuthenticatorTest extends SapphireTest
             return;
         }
 
-        // Enforce dummy validation (this can otherwise be influenced by recipe config)
-        Deprecation::withSuppressedNotice(
-            fn() => PasswordValidator::singleton()
-            ->setMinLength(0)
-            ->setTestNames([])
-        );
+        // Remove password validation
+        Member::set_password_validator(null);
     }
 
     protected function tearDown(): void