{"id":"CVE-2026-9571","summary":"Deactivated user accounts can continue to obtain valid OAuth access tokens via refresh token grant in Mattermost","details":"Mattermost versions 11.7.x \u003c= 11.7.2, 11.6.x \u003c= 11.6.4, 10.11.x \u003c= 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","modified":"2026-07-16T03:45:53.337938341Z","published":"2026-07-13T07:50:55.793Z","database_specific":{"cwe_ids":["CWE-305"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/9xxx/CVE-2026-9571.json","unresolved_ranges":[{"extracted_events":[{"introduced":"11.7.0"},{"last_affected":"11.7.2"},{"introduced":"11.6.0"},{"last_affected":"11.6.4"},{"introduced":"10.11.0"},{"last_affected":"10.11.19"}],"source":"AFFECTED_FIELD"}],"cna_assigner":"Mattermost"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/9xxx/CVE-2026-9571.json"},{"type":"ADVISORY","url":"https://mattermost.com/security-updates"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-9571"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/mattermost/mattermost","events":[{"introduced":"5b955468ea1ea8b56c0fb10feb258a36a767d7bb"},{"fixed":"31b97d9ee1e020ca63f2169e4daab4aa0519a727"},{"introduced":"d4f4e78835e86e2e76f76bfe797623076f5c9835"},{"fixed":"b94397a68c6129bb904dcb0ab7643b188f2717b0"},{"introduced":"a9e574a82633915f22071f0d7ca2b006f249ec2a"},{"fixed":"28b63b15f73e0ed02d0da0018e06d88c47a77c48"}],"database_specific":{"cpe":"cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"10.11.0"},{"fixed":"10.11.20"},{"introduced":"11.6.0"},{"fixed":"11.6.5"},{"introduced":"11.7.0"},{"fixed":"11.7.3"}],"source":"CPE_RANGE"}}],"versions":["v10.11.19","v11.6.4","v10.11.19-rc1","v11.7.2","v11.6.3","v10.11.18","v11.7.1","v11.6.2","v10.11.17","v10.11.16","v11.7.0","mattermost-redux@11.7.0","@mattermost/types@11.7.0","@mattermost/shared@11.7.0","@mattermost/client@11.7.0","v10.11.15-rc1","v10.11.15","v11.6.1-rc1","v11.6.1","v10.11.14","v11.6.0","v10.11.14-rc1","v10.11.13","v10.11.13-rc1","v10.11.12","v10.11.11-rc2","v10.11.11","v10.11.11-rc1","v10.11.10","v10.11.9","v10.11.9-rc1","v10.11.8","v10.11.7","v10.11.6","v10.11.5","v10.11.4-rc3","v10.11.4","v10.11.4-rc2","v10.11.4-rc1","v10.11.3","v10.11.2-rc2","v10.11.2","v10.11.2-rc1","v10.11.1","v10.11.1-rc1","v10.11.0-rc3","v10.11.0","mattermost-redux@10.11.0","@mattermost/types@10.11.0","@mattermost/client@10.11.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-9571.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N"}]}