{"id":"CVE-2026-9571","aliases":["EUVD-2026-43305","GHSA-4v7j-4mvr-5975"],"status":"published","title":"Deactivated user accounts can continue to obtain valid OAuth access tokens via refresh token grant in Mattermost","description":"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","severity":{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00303,"percentile":0.23249,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-305"],"published":"2026-07-13T07:50:55Z","modified":"2026-10-28T02:30:52Z","products":[{"vendor":"mattermost","product":"mattermost"},{"vendor":"mattermost","product":"mattermost_server"}],"references":[{"url":"https://mattermost.com/security-updates","tags":["vendor-advisory","Vendor Advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-9571","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-4v7j-4mvr-5975"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/9xxx/CVE-2026-9571.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-9571","title":"Deactivated user accounts can continue to obtain valid OAuth access tokens via refresh token grant in Mattermost","description":"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","status":"published","published":"2026-07-13T07:50:55.793Z","modified":"2026-07-15T04:00:07.436Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-305"],"updated_at":"2026-11-02T13:42:37.965383Z"}],"euvd":[{"id":"EUVD-2026-43305","description":"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","status":"published","published":"2026-07-13T07:50:55Z","modified":"2026-07-15T04:00:07Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N","level":"medium"}],"updated_at":"2026-11-02T18:19:53.678292Z"}],"ghsa":[{"id":"GHSA-4v7j-4mvr-5975","title":"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...","description":"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","status":"published","published":"2026-07-13T09:31:43Z","modified":"2026-07-13T09:31:50Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N","level":"medium"}],"cwes":["CWE-305"],"updated_at":"2026-11-02T15:09:24.680615Z"}],"nvd":[{"id":"CVE-2026-9571","description":"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","status":"published","published":"2026-07-13T09:16:25.017Z","modified":"2026-07-15T05:17:25.443Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N","level":"medium","assessor":"secondary"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-305"],"updated_at":"2026-11-02T14:12:28.771746Z"}],"osv":[{"id":"CVE-2026-9571","title":"Deactivated user accounts can continue to obtain valid OAuth access tokens via refresh token grant in Mattermost","description":"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","status":"published","published":"2026-07-13T07:50:55.793Z","modified":"2026-10-28T02:30:52.45779128Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N","level":"medium"}],"cwes":["CWE-305"],"updated_at":"2026-11-02T15:45:20.931171Z"}]}}