What’s Vulnerable › Vulnerabilities
CVE-2026-8340: Concrete CMS 9.5.0 and below is vulnerable to CSRF via Backend\File::approveVersion
- Severity: medium (CVSS 4.3 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.1% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-05-22 · updated 2026-07-23
- Weakness: CWE-352
Description
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an attacker-chosen previously-uploaded version (downgrade to an older version of a file, or activation of a co-editor's unpublished version).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.
Affected products
- Concrete CMS: before 9.5.1 — fixed in 9.5.1
How to fix
Upgrade to a fixed version: Concrete CMS 9.5.1. Check the vendor advisory for mitigations.
References
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