Silverstripe Framework is a PHP framework which powers the Silverstripe CMS. Prior to 5.3.23, bad actor with access to edit content in the CMS could 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 sanitized on the client-side, but server-side sanitization doesn't catch it. The server-side sanitization logic has been updated to sanitize against this attack. This vulnerability is fixed in 5.3.23.

AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

CWE-79

https://github.com/silverstripe/silverstripe-framework/commit/e99cfd62d160d145a76fcf9631e6b11226e42358

https://github.com/silverstripe/silverstripe-framework/security/advisories/GHSA-rhx4-hvx9-j387

https://www.silverstripe.org/download/security-releases/cve-2025-30148