diff --git a/src/Control/Director.php b/src/Control/Director.php
index 3ac23350e..8c3a0f8f2 100644
--- a/src/Control/Director.php
+++ b/src/Control/Director.php
@@ -825,10 +825,11 @@ class Director implements TemplateGlobalProvider
         return (
             // Base check for existence of a host on a compliant URL
             parse_url($url ?? '', PHP_URL_HOST)
-            // Check for more than one leading slash without a protocol.
+            // Check for more than one leading slash (forward or backward) without a protocol.
             // While not a RFC compliant absolute URL, it is completed to a valid URL by some browsers,
             // and hence a potential security risk. Single leading slashes are not an issue though.
-            || preg_match('%^\s*/{2,}%', $url ?? '')
+            // Note: Need 4 backslashes to have a single non-escaped backslash for regex.
+            || preg_match('%^\s*(\\\\|/){2,}%', $url ?? '')
             || (
                 // If a colon is found, check if it's part of a valid scheme definition
                 // (meaning its not preceded by a slash).
diff --git a/src/Forms/GridField/GridFieldPrintButton.php b/src/Forms/GridField/GridFieldPrintButton.php
index 1ec2be669..1fc965808 100644
--- a/src/Forms/GridField/GridFieldPrintButton.php
+++ b/src/Forms/GridField/GridFieldPrintButton.php
@@ -228,21 +228,23 @@ class GridFieldPrintButton extends AbstractGridFieldComponent implements GridFie
 
         /** @var DataObject $item */
         foreach ($items->limit(null) as $item) {
-            $itemRow = new ArrayList();
+            if (!$item->hasMethod('canView') || $item->canView()) {
+                $itemRow = new ArrayList();
 
-            foreach ($printColumns as $field => $label) {
-                $value = $gridFieldColumnsComponent
-                    ? strip_tags($gridFieldColumnsComponent->getColumnContent($gridField, $item, $field))
-                    : $gridField->getDataFieldValue($item, $field);
+                foreach ($printColumns as $field => $label) {
+                    $value = $gridFieldColumnsComponent
+                        ? strip_tags($gridFieldColumnsComponent->getColumnContent($gridField, $item, $field))
+                        : $gridField->getDataFieldValue($item, $field);
 
-                $itemRow->push(new ArrayData([
-                    "CellString" => $value,
+                    $itemRow->push(new ArrayData([
+                        "CellString" => $value,
+                    ]));
+                }
+
+                $itemRows->push(new ArrayData([
+                    "ItemRow" => $itemRow
                 ]));
             }
-
-            $itemRows->push(new ArrayData([
-                "ItemRow" => $itemRow
-            ]));
             if ($item->hasMethod('destroy')) {
                 $item->destroy();
             }
diff --git a/tests/php/Control/DirectorTest.php b/tests/php/Control/DirectorTest.php
index 44c9e1980..febb59306 100644
--- a/tests/php/Control/DirectorTest.php
+++ b/tests/php/Control/DirectorTest.php
@@ -233,6 +233,9 @@ class DirectorTest extends SapphireTest
     public function testIsAbsoluteUrl()
     {
         $this->assertTrue(Director::is_absolute_url('http://test.com/testpage'));
+        $this->assertTrue(Director::is_absolute_url('https:/\\test.com'));
+        $this->assertTrue(Director::is_absolute_url('https:\\/test.com'));
+        $this->assertTrue(Director::is_absolute_url('https:\\\\test.com'));
         $this->assertTrue(Director::is_absolute_url('ftp://test.com'));
         $this->assertFalse(Director::is_absolute_url('test.com/testpage'));
         $this->assertFalse(Director::is_absolute_url('/relative'));
@@ -242,6 +245,11 @@ class DirectorTest extends SapphireTest
         $this->assertTrue(Director::is_absolute_url("https://test.com/?url=http://foo.com"));
         $this->assertTrue(Director::is_absolute_url("trickparseurl:http://test.com"));
         $this->assertTrue(Director::is_absolute_url('//test.com'));
+        $this->assertTrue(Director::is_absolute_url('\\/\\/test.com'));
+        $this->assertTrue(Director::is_absolute_url('\/\/test.com'));
+        $this->assertTrue(Director::is_absolute_url('/\\test.com'));
+        $this->assertTrue(Director::is_absolute_url('\\\\test.com'));
+        $this->assertFalse(Director::is_absolute_url('\\test.com'));
         $this->assertTrue(Director::is_absolute_url('/////test.com'));
         $this->assertTrue(Director::is_absolute_url('  ///test.com'));
         $this->assertTrue(Director::is_absolute_url('http:test.com'));
@@ -259,8 +267,17 @@ class DirectorTest extends SapphireTest
     {
         $this->assertFalse(Director::is_relative_url('http://test.com'));
         $this->assertFalse(Director::is_relative_url('https://test.com'));
+        $this->assertFalse(Director::is_relative_url('https:/\\test.com'));
+        $this->assertFalse(Director::is_relative_url('https:\\/test.com'));
+        $this->assertFalse(Director::is_relative_url('https:\\\\test.com'));
         $this->assertFalse(Director::is_relative_url('   https://test.com/testpage   '));
         $this->assertTrue(Director::is_relative_url('test.com/testpage'));
+        $this->assertFalse(Director::is_relative_url('//test.com'));
+        $this->assertFalse(Director::is_relative_url('\\/\\/test.com'));
+        $this->assertFalse(Director::is_relative_url('\/\/test.com'));
+        $this->assertFalse(Director::is_relative_url('/\\test.com'));
+        $this->assertFalse(Director::is_relative_url('\\\\test.com'));
+        $this->assertTrue(Director::is_relative_url('\\test.com'));
         $this->assertFalse(Director::is_relative_url('ftp://test.com'));
         $this->assertTrue(Director::is_relative_url('/relative'));
         $this->assertTrue(Director::is_relative_url('relative'));
@@ -402,17 +419,34 @@ class DirectorTest extends SapphireTest
         );
     }
 
-    /**
-     * Mostly tested by {@link testIsRelativeUrl()},
-     * just adding the host name matching aspect here.
-     */
     public function testIsSiteUrl()
     {
-        $this->assertFalse(Director::is_site_url("http://test.com"));
+        $this->assertFalse(Director::is_site_url('http://test.com'));
+        $this->assertTrue(Director::is_site_url('/relative-path'));
+        $this->assertTrue(Director::is_site_url('relative-path'));
         $this->assertTrue(Director::is_site_url(Director::absoluteBaseURL()));
-        $this->assertFalse(Director::is_site_url("http://test.com?url=" . Director::absoluteBaseURL()));
-        $this->assertFalse(Director::is_site_url("http://test.com?url=" . urlencode(Director::absoluteBaseURL() ?? '')));
-        $this->assertFalse(Director::is_site_url("//test.com?url=" . Director::absoluteBaseURL()));
+        $this->assertFalse(Director::is_site_url('http://test.com?url=' . Director::absoluteBaseURL()));
+        $this->assertFalse(Director::is_site_url('http://test.com?url=' . urlencode(Director::absoluteBaseURL() ?? '')));
+        $this->assertFalse(Director::is_site_url('http:\\\\test.com'));
+        $this->assertFalse(Director::is_site_url('http:\\\\test.com?url=' . Director::absoluteBaseURL()));
+        $this->assertFalse(Director::is_site_url('http:\\\\test.com?url=' . urlencode(Director::absoluteBaseURL() ?? '')));
+        $this->assertFalse(Director::is_site_url('http:\\/test.com'));
+        $this->assertFalse(Director::is_site_url('http:\\/test.com?url=' . Director::absoluteBaseURL()));
+        $this->assertFalse(Director::is_site_url('http:\\/test.com?url=' . urlencode(Director::absoluteBaseURL() ?? '')));
+        $this->assertFalse(Director::is_site_url('//test.com'));
+        $this->assertFalse(Director::is_site_url('//test.com?url=' . Director::absoluteBaseURL()));
+        $this->assertFalse(Director::is_site_url('\\/\\/test.com'));
+        $this->assertFalse(Director::is_site_url('\\/\\/test.com?url=' . Director::absoluteBaseURL()));
+        $this->assertFalse(Director::is_site_url('\/\/test.com'));
+        $this->assertFalse(Director::is_site_url('\/\/test.com?url=' . Director::absoluteBaseURL()));
+        $this->assertFalse(Director::is_site_url('\\/test.com'));
+        $this->assertFalse(Director::is_site_url('\\/test.com?url=' . Director::absoluteBaseURL()));
+        $this->assertFalse(Director::is_site_url('/\\test.com'));
+        $this->assertFalse(Director::is_site_url('/\\test.com?url=' . Director::absoluteBaseURL()));
+        $this->assertFalse(Director::is_site_url('\\\\test.com'));
+        $this->assertFalse(Director::is_site_url('\\\\test.com?url=' . Director::absoluteBaseURL()));
+        $this->assertTrue(Director::is_site_url('\\test.com'));
+        $this->assertTrue(Director::is_site_url('\\test.com?url=' . Director::absoluteBaseURL()));
         $this->assertFalse(Director::is_site_url('http://google.com\@test.com'));
         $this->assertFalse(Director::is_site_url('http://google.com/@test.com'));
         $this->assertFalse(Director::is_site_url('http://google.com:pass\@test.com'));
diff --git a/tests/php/Forms/GridField/GridFieldPrintButtonTest.php b/tests/php/Forms/GridField/GridFieldPrintButtonTest.php
index 59e73a494..f78c305ba 100644
--- a/tests/php/Forms/GridField/GridFieldPrintButtonTest.php
+++ b/tests/php/Forms/GridField/GridFieldPrintButtonTest.php
@@ -32,6 +32,19 @@ class GridFieldPrintButtonTest extends SapphireTest
     }
 
     public function testLimit()
+    {
+        $this->assertEquals(42, $this->getTestableRows()->count());
+    }
+
+    public function testCanViewIsRespected()
+    {
+        $orig = TestObject::$canView;
+        TestObject::$canView = false;
+        $this->assertEquals(0, $this->getTestableRows()->count());
+        TestObject::$canView = $orig;
+    }
+
+    private function getTestableRows()
     {
         $list = TestObject::get();
 
@@ -48,7 +61,6 @@ class GridFieldPrintButtonTest extends SapphireTest
 
         // Printed data should ignore pagination limit
         $printData = $button->generatePrintData($gridField);
-        $rows = $printData->ItemRows;
-        $this->assertEquals(42, $rows->count());
+        return $printData->ItemRows;
     }
 }
diff --git a/tests/php/Forms/GridField/GridFieldPrintButtonTest/TestObject.php b/tests/php/Forms/GridField/GridFieldPrintButtonTest/TestObject.php
index 2e8f80cc9..dd5638d09 100644
--- a/tests/php/Forms/GridField/GridFieldPrintButtonTest/TestObject.php
+++ b/tests/php/Forms/GridField/GridFieldPrintButtonTest/TestObject.php
@@ -12,4 +12,11 @@ class TestObject extends DataObject implements TestOnly
     private static $db = [
         'Name' => 'Varchar'
     ];
+
+    public static bool $canView = true;
+
+    public function canView($member = null)
+    {
+        return static::$canView;
+    }
 }