{"id":"CVE-2026-81901","summary":"Concrete CMS 9.2.0 to 9.5.2 is vulnerable to stored XSS due to missing authorization in the `PUT /pages/{cID}` endpoint","details":"In Concrete CMS 9.2.0 through 9.5.2, the REST API page update endpoint (PUT /ccm/api/1.0/pages/{cID}) did not enforce page-property, page-template, or page-type authorization. A user granted only content-editing rights on a page could therefore alter its properties, template, and type through the API, and could set the header_extra_content attribute, which is rendered unescaped into the head element of every page, to persist JavaScript that executed in the browser of every visitor, including higher-privileged reviewers who approve the page version. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 7.2 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N. Thanks Yonatan Drori from Tenzai for reporting.","modified":"2026-09-17T03:31:04.515431031Z","published":"2026-09-14T20:38:54.393Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/81xxx/CVE-2026-81901.json","cna_assigner":"ConcreteCMS","cwe_ids":["CWE-862"]},"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-2026-81901.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-81901"},{"type":"PACKAGE","url":"https://github.com/concretecms/concretecms"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/concretecms/concretecms","events":[{"introduced":"6462c74b64a9d8919cc4a16f78880079dc6878ff"},{"last_affected":"8fe9708072c3815a5df719b592e4b23b43b4ff7a"}],"database_specific":{"extracted_events":[{"introduced":"9.2.0"},{"last_affected":"9.5.2"}],"source":"AFFECTED_FIELD"}}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-81901.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N"}]}