{"id":"CVE-2026-82920","title":"Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7 fail to enforce authorization boundaries on the access control policy update endpoint which allows a channel or team administrator to detach a system-assigned ABAC …","summary":"Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7 fail to enforce authorization boundaries on the access control policy update endpoint which allows a channel or team administrator to detach a system-assigned ABAC …","severity":"medium","cvss":5.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N","cwe":["CWE-863"],"vendor":"mattermost","product":"mattermost_server","affected":["mattermost_server >= 11.7.0, < 11.7.8","mattermost_server >= 11.8.0, < 11.8.5","mattermost_server >= 11.9.0, < 11.9.1"],"patched":["mattermost_server 11.9.1"],"published":"2026-09-14","updated":"2026-10-07","sourceUpdated":"2026-10-07T18:04:00.843","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-82920","references":[{"url":"https://mattermost.com/security-updates","label":"responsibledisclosure@mattermost.com"}],"tags":["nvd","cve.org"],"epss":0.00255,"epssPercentile":0.16974,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-09-14T19:13:28.324125Z"},"ingestedAt":"2026-09-14T15:23:07.422Z","slug":"CVE-2026-82920","body":"## Overview\n\nMattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7 fail to enforce authorization boundaries on the access control policy update endpoint which allows a channel or team administrator to detach a system-assigned ABAC parent policy via a crafted PUT /api/v4/access_control_policies request with an empty imports list.. Mattermost Advisory ID: MMSA-2026-00724\n\n## Affected\n\n- `mattermost_server >= 11.7.0, < 11.7.8`\n- `mattermost_server >= 11.8.0, < 11.8.5`\n- `mattermost_server >= 11.9.0, < 11.9.1`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `mattermost_server 11.9.1`","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}