Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
Concrete CMS versions before 9.5.1 (Packagist package concrete5/concrete5) are affected by a flaw in the DeleteFile controller, where the CSRF token check is inverted, so requests with a missing or invalid token still delete files. An attacker could exploit this through a cross-site request forgery attack against a logged-in user who has permission to edit conversation messages, causing unauthorized file deletion. The fix is to upgrade to version 9.5.1.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 2.3 | Low | 4.0 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N | CNA (ConcreteCMS) |
- CISA KEV Not listed.
- EPSS 0.0012, the 1st percentile, on 11 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 14:02 UTC First seen by agentprime
- 31 Oct 2026, 14:02 UTC Confirmed by OSV