CVE-2026-8340: low-severity vulnerability in Concrete CMS
Concrete CMS 9.5.0 and below is vulnerable to CSRF via Backend\File::approveVersion
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
8Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 2.3epss 0.1%
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an attacker-chosen previously-uploaded version (downgrade to an older version of a file, or activation of a co-editor's unpublished version).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.
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
Affected products
Concrete CMS · Concrete CMSRelated CVEs — Concrete CMS
In the same product, most dangerous first.
CVE-2026-18110HIGHConcrete CMS 9.0.0 through 9.5.2 is vulnerable to missing authorization in the user selector autocomplete endpoint (/ccm/system/user/autocomplete), allowing an unauthenticated attacker to retrieve the complete backend user directory — internal ID, usernameEPSS 1.6%CVE-2026-6826MEDIUMConcrete 9.5.0 and below has file usage disclosure via missing permission check in Usage controllerEPSS 1.5%CVE-2024-1247LOWConcrete CMS version 9 before 9.2.5 vulnerable to stored XSS via the Role Name fieldEPSS 1.2%CVE-2026-8134CRITICALConcrete CMS 9.5.0 and below is vulnerable to Authenticated RCE via Composer customTemplate Path Traversal leading to PHP File InclusionEPSS 0.7%CVE-2026-3452HIGHConcrete CMS below 9.4.8 is vulnerable to stored deserialization leading to RCE in the Express Entry List block.EPSS 0.7%CVE-2011-3183—CVE-2011-3183EPSS 0.7%