{"id":"CVE-2026-81920","title":"Concrete CMS below 9.5.3 was vulnerable to Cross-Site Request Forgery in the dashboard SEO Excluded Words page","summary":"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 no…","severity":"medium","cvss":4.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N","cwe":["CWE-352"],"vendor":"concretecms","product":"concrete_cms","affected":["concrete_cms < 9.5.3"],"patched":["concrete_cms 9.5.3"],"published":"2026-09-15","updated":"2026-09-18","sourceUpdated":"2026-09-18T15:27:27.317","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-81920","references":[{"url":"https://documentation.concretecms.org/developers/introduction/version-history/953-release-notes","label":"ff5b8ace-8b95-4078-9743-eac1ca5451de"}],"tags":["nvd","cve.org","score-dispute"],"epss":0.0013,"epssPercentile":0.02995,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-09-15T19:40:50.225213Z"},"scores":{"nvd":4.3,"cna":2.3},"ingestedAt":"2026-09-15T19:42:58.809Z","slug":"CVE-2026-81920","body":"## Overview\n\nConcrete 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.\n\n## Affected\n\n- `concrete_cms < 9.5.3`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `concrete_cms 9.5.3`","depth":"sunlit","depthScore":24,"depthScoreParts":{"impact":23.7,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":206895,"id":"CVE-2026-81920","ts":1789746312137,"field":"cvss","old":"2.3","new":"4.3"},{"seq":206894,"id":"CVE-2026-81920","ts":1789746312137,"field":"severity","old":"low","new":"medium"}]}