CVE-2026-81924

Medium

Description

Concrete CMS before 9.5.3 is vulnerable to Cross-Site Request Forgery (CSRF) in the theme page-template activation feature. The Dashboard theme Inspect controller's activate_files() action created PageTemplate records from attacker-supplied pageTemplates[] values without validating an anti-CSRF token.A remote attacker could host a page that auto-submitted a forged POST request; when a signed-in administrator visited it, the request executed under the administrator's session and created theme page-template records, changing site configuration without the administrator's consent. 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.

SeverityMedium
CVSS6.5
Exploit probability—
ProductConcretecms Concrete Cms
PublishedSep 15, 2026
First seenSep 15, 2026

How to fix

Update
  • concretecms concrete_cms9.5.3 or later

Affected products

ProductAffected versionsFixed in
concretecms concrete_cmsv < 9.5.39.5.3

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