{"id":"CVE-2026-91181","title":"Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 Fail to sanitize Team objects returned by the data retention teams endpoint which allows an authenticated user holding only the read-only Data …","summary":"Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 Fail to sanitize Team objects returned by the data retention teams endpoint which allows an authenticated user holding only the read-only Data …","severity":"medium","cvss":6.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N","cwe":["CWE-863"],"vendor":"mattermost","product":"mattermost_server","affected":["mattermost_server >= 10.11.0, < 10.11.23","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":"2026-10-07T16:49:26.633","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-91181","references":[{"url":"https://mattermost.com/security-updates","label":"responsibledisclosure@mattermost.com"}],"tags":["nvd","cve.org"],"epss":0.00387,"epssPercentile":0.32601,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-09-15T19:15:24.266955Z"},"ingestedAt":"2026-09-14T22:16:09.898Z","slug":"CVE-2026-91181","body":"## Overview\n\nMattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 Fail to sanitize Team objects returned by the data retention teams endpoint which allows an authenticated user holding only the read-only Data Retention Policy permission to obtain a private team's secret invite_id and email, and use it to join the team without authorization, via GET /api/v4/data_retention/policies/{policy_id}/teams.. Mattermost Advisory ID: MMSA-2026-00702\n\n## Affected\n\n- `mattermost_server >= 10.11.0, < 10.11.23`\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":36,"depthScoreParts":{"impact":35.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}