{"id":"CVE-2026-81909","title":"Concrete CMS 9 through 9.5.2 is vulnerable to Missing Authorization in the orphaned-block alias route, allowing an authenticated editor to disclose and force-delete arbitrary blocks","summary":"Concrete CMS 9 through 9.5.2 is vulnerable to Missing Authorization in the block alias route (Process::alias() in concrete/controllers/backend/block/process.php).It does not verify that the referenced block is genuinely orphaned on the t…","severity":"medium","cvss":5.9,"cvssVector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N","cvssSource":"cna","cwe":["CWE-862"],"vendor":"Concrete CMS","product":"Concrete CMS","affected":["concrete_cms >= 9.0.0 <= 9.5.2"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-09-11T17:58:10.598724Z"},"published":"2026-09-11","updated":"2026-09-11","sourceUpdated":"2026-09-11T17:58:35.013Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-81909","references":[{"url":"https://documentation.concretecms.org/developers/introduction/version-history/953-release-notes"}],"tags":["cve.org"],"epss":0.0026,"epssPercentile":0.18025,"ingestedAt":"2026-09-14T00:35:28.535Z","slug":"CVE-2026-81909","body":"## Overview\n\nConcrete CMS 9 through 9.5.2 is vulnerable to Missing Authorization in the block alias route (Process::alias() in concrete/controllers/backend/block/process.php).It does not verify that the referenced block is genuinely orphaned on the target page, nor that the caller holds any permission over the source block. A user granted only an area-scoped add_block_to_area delegation on their own page can therefore pass any block ID on the site: the source block's content is duplicated into an area the rogue editor controls, disclosing that content, and the original block is then force-deleted in the same request, destroying arbitrary site content. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 5.9 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks Yonatan Drori from Tenzai for reporting.\n\n## Affected\n\n- `concrete_cms >= 9.0.0 <= 9.5.2`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":33,"depthScoreParts":{"impact":32.5,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}