{"id":"CVE-2026-8340","aliases":["GHSA-xjg6-5v39-v7fc"],"url":"https://o3.security/vulnerability/CVE-2026-8340","summary":"Concrete CMS 9.5.0 and below is vulnerable to CSRF via Backend\\File::approveVersion","details":"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an attacker-chosen previously-uploaded version (downgrade to an older version of a file, or activation of a co-editor's unpublished version).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.","published":"2026-05-22T13:58:55.844Z","modified":"2026-08-12T03:51:20.067195022Z","cvss":null,"epss":{"score":0.00103,"percentile":0.01116,"asOf":"2026-08-16"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Packagist","name":"concrete5/concrete5","fixedVersion":"9.5.1"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/8xxx/CVE-2026-8340.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-8340"},{"type":"PACKAGE","url":"https://github.com/concretecms/concretecms"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:20.067195022Z"}}