CVE-2026-81923: low-severity vulnerability in Concrete CMS
Concrete CMS below 9.5.3 is missing authorization in the SEO Bulk Update Meta Tags editor
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 2.1epss 0.3%
In Concrete CMS before 9.5.3, the SEO Bulk Update Meta Tags editor did not check per-page edit permissions before saving. The saveRecord() action validated the per-page CSRF token but never called canEditPageProperties() for the target page, so a user who was granted access to the bulk SEO tool and could view (but not edit) a given page was able to change that page's meta title, meta description, and URL handle outside their edit scope, tampering with the presentation and live URLs of otherwise protected content. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 2.1 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Andrew Gonzalez for reporting.
CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/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%