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 has a XSS in form messages