Executive brief
Concrete CMS, a popular web content management system, is vulnerable to a security flaw where an attacker can trick an administrator into performing unintended actions. Specifically, if a logged-in administrator visits a malicious website, that site could silently trigger bulk cache operations on the CMS without the user's consent. This could lead to unauthorized changes in how the website handles temporary data, potentially impacting site performance or integrity.
Technical details
A Cross-Site Request Forgery (CSRF) vulnerability exists in Concrete CMS versions 9.0.0RC1 through 9.5.0 within the 'concrete/controllers/dialog/page/bulk/cache' component. The application fails to properly validate CSRF tokens for requests handled by this controller. An unauthenticated remote attacker can exploit this by enticing a privileged user to visit a specially crafted webpage. If successful, the attacker can execute bulk cache management operations in the context of the victim's session. The issue is resolved in version 9.5.1.
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 details