# 3.1.9 ## Upgrading ### File permissions This release makes an important change to File DataObject permissions in order to close a vulnerability in file modification privileges. In 3.1.8 and below, any part of a website where user interaction could potentially modify a file (such as an UploadField being used on the frontend) permissions may not be adequately checked, meaning in some cases non-authorised (or even non-authenticated) users could make changes to assets. This is because the File DataObject reports that any user has canEdit privileges on it. By default the minimum necessary permission required by any user to modify files has been changed to CMS_ACCESS_AssetAdmin. This permission value was historically required in 3.0 and has now been restored. In order to update a site to 3.1.9 it may be necessary to make sure that this permission requirement still makes sense to any business logic, and it may also be necessary to apply another permission. This can be done by creating an extension to File which applies the custom permission. E.g. :::php