{"id":"CVE-2026-81920","summary":"Concrete CMS below 9.5.3 is vulnerable to Cross-Site Request Forgery (CSRF) in Dashboard SEO Excluded Words Reset Endpoint","details":"Concrete CMS below 9.5.3 was vulnerable to Cross-Site Request Forgery in the dashboard SEO Excluded Words page. The reset() controller action cleared the administrator-configured reserved-word list (concrete.seo.exclude_words) but did not validate the anti-CSRF token that the reset modal emitted, and it did not restrict the request to the POST method. A remote attacker who lured an authenticated user with SEO access to a crafted page could revert the reserved-word list to its default and silently alter future URL-slug generation for pages, files, topics, and other objects created through the Text urlify service, undoing the site's configured SEO slug policy. The Concrete CMS security team gave this vulnerability a CVSS v4.0 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 riodrwn for reporting.","modified":"2026-09-18T03:31:03.514612011Z","published":"2026-09-15T18:46:30.484Z","database_specific":{"cwe_ids":["CWE-352"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/81xxx/CVE-2026-81920.json","cna_assigner":"ConcreteCMS"},"references":[{"type":"ADVISORY","url":"https://documentation.concretecms.org/developers/introduction/version-history/953-release-notes"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/81xxx/CVE-2026-81920.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-81920"},{"type":"PACKAGE","url":"https://github.com/concretecms/concretecms"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/concretecms/concretecms","events":[{"introduced":"0"},{"last_affected":"8fe9708072c3815a5df719b592e4b23b43b4ff7a"}],"database_specific":{"source":"AFFECTED_FIELD","extracted_events":[{"introduced":"5.0.0"},{"last_affected":"9.5.2"}]}}],"versions":["9.5.2","9.5.1","9.5.0","9.5.0RC2","9.5.0RC1","9.4.4","9.4.3","9.4.2","9.4.1","9.4.0","9.4.0RC2","9.4.0RC1","9.3.7","9.3.6","9.3.5","9.3.0","9.3.4","9.3.3","9.3.2","9.3.1","8.4.1","8.3.1","8.2.1","8.2.0","8.2.0RC2","8.1.0","5.7.5.7","5.7.5.6","5.7.5.5","5.7.5.2","5.7.4.1","5.7.3.1","5.7.3","5.7.2.1","5.7.2","5.7.0.4","5.7.1","5.7.0.3","5.7.0.1","5.7.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-81920.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"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"}]}