Security Advisory
CVE-2026-8340
CVE vulnerability detail — eXtreme Datacenter Security Operations
Description
Concrete CMS 9.5.0 and below is vulnerable to CSRF via BackendFile::approveVersion. Victim with edit_file_contents permission is CSRFd into publishing an attacker-chosen previously-uploaded version (downgrade to an older version of a file, or activation of a co-editors unpublished version).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.