Silverstripe Framework is a PHP framework which powers the Silverstripe CMS. In some cases, form messages can contain HTML markup. This is an intentional feature, allowing links and other relevant HTML markup for the given message. Some form messages include content that the user can provide. There are scenarios in the CMS where that content doesn't get correctly sanitised prior to being included in the form message, resulting in an XSS vulnerability. This issue has been addressed in silverstripe/framework version 5.3.8 and users are advised to upgrade. There are no known workarounds for this vulnerability.

Silverstripe framework is the PHP framework forming the base for the Silverstripe CMS. In affected versions a bad actor with access to edit content in the CMS could add send a specifically crafted encoded payload to the server, which could be used to inject a JavaScript payload on the front end of the site. The payload would be sanitised on the client-side, but server-side sanitisation doesn't catch it. The server-side sanitisation logic has been updated to sanitise against this type of attack in version 5.2.16. All users are advised to upgrade. There are no known workarounds for this vulnerability.