CVE-2026-8340CWE-352

Concrete CMS 9.5.0 and below is vulnerable to CSRF via Backend\File::approveVersion

Low · published May 22, 2026

CVSS v4.0
2.3
EPSS
0%
Percentile
3.7
In the wild
Unconfirmed
What it is

Concrete CMS 9.5.0 and below is vulnerable to CSRF via Backend\File::approveVersion. Victim with edit_file_contents permission is CSRF'd into publishing an attacker-chosen previously-uploaded version (downgrade to an older version of a file, or activation of a co-editor's unpublished version). The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 2.3 with vector 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. Thanks Winston Crooker for reporting.

The record
Technical detail
CVSS v4.0
2.3 · LOW
Vector
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
EPSS
0.00148 · 3.7th percentile
Weakness
CWE-352 · Cross-Site Request Forgery (CSRF)
Published
2026-05-22T13:58Z
EPSS history
Timeline
  • 22 MAY 13:58Z
    Concrete CMS 9.5.0 and below is vulnerable to CSRF via Backend\File::approveVersion
    cvelistv5