Executive brief
Concrete CMS, a popular content management system, is vulnerable to a security flaw that could allow an attacker to trick an administrator into unintentionally removing a folder from their 'favorites' list. This occurs because the system fails to verify that the request was intentionally initiated by the user. While the impact is limited to organizational preferences within the file manager, it represents a lapse in security controls that could be exploited through malicious links or websites.
Technical details
A Cross-Site Request Forgery (CSRF) vulnerability exists in Concrete CMS versions 9.0.0RC1 through 9.5.0. The 'removeFavoriteFolder' method in the backend file controller (concrete/controllers/backend/file) does not implement sufficient CSRF token validation. An attacker can exploit this by inducing an authenticated user to visit a malicious webpage or click a crafted link, leading to the unauthorized removal of favorite folders from the user's workspace. The vulnerability is addressed in version 9.5.1 by implementing proper request validation.
Affected products
- Concrete CMS Concrete CMS 9.0.0RC1 to 9.5.0
Timeline
- 2026-05-21: disclosed: NVD publication date
- 2026-05-22: advisory: GitHub Advisory published
- 2026-06-24: patched: Advisory updated with patch information for version 9.5.1