{"id":"CVE-2026-9571","title":"Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to invalidate OAuth refresh tokens upon user account deactivation, which allows a deactivated user or an attacker in possession of a valid refresh token to …","summary":"Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to invalidate OAuth refresh tokens upon user account deactivation, which allows a deactivated user or an attacker in possession of a valid refresh token to …","severity":"medium","cvss":5.9,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N","cwe":["CWE-305"],"published":"2026-07-13","updated":"2026-07-13","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-9571","references":[{"url":"https://mattermost.com/security-updates","label":"responsibledisclosure@mattermost.com"}],"tags":["nvd"],"ingestedAt":"2026-07-13T12:26:58.155Z","epss":0.00303,"epssPercentile":0.23197,"slug":"CVE-2026-9571","body":"## Overview\n\nMattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to invalidate OAuth refresh tokens upon user account deactivation, which allows a deactivated user or an attacker in possession of a valid refresh token to obtain new functional access tokens via the OAuth refresh token grant endpoint.. Mattermost Advisory ID: MMSA-2026-00680\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":[]}