{"id":"CVE-2026-6739","aliases":["GHSA-m2w9-h2mm-79qr"],"url":"https://o3.security/vulnerability/CVE-2026-6739","summary":"Mattermost: Delegated admins could patch protected default system roles","details":"Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 fail to require system-level permission when patching protected default system roles, which allows authenticated users with delegated user-management permissions to escalate privileges by altering built-in role permissions via the role patch API.. Mattermost Advisory ID: MMSA-2026-00656","published":"2026-06-12T15:49:14.444Z","modified":"2026-09-29T18:26:39.462492418Z","cvss":{"score":6.7,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:L"},"epss":{"score":0.00257,"percentile":0.17157,"asOf":"2026-09-02"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","fixedVersion":"11.6.1"},{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","fixedVersion":"11.5.5"},{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server","fixedVersion":"10.11.17"},{"ecosystem":"Go","name":"github.com/mattermost/mattermost/server/v8","fixedVersion":"8.0.0-20260501142004-99b73d4c4acf"}],"fix":{"url":"https://github.com/mattermost/mattermost/pull/36197","label":"mattermost/mattermost#36197"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/6xxx/CVE-2026-6739.json"},{"type":"ADVISORY","url":"https://mattermost.com/security-updates"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-6739"},{"type":"WEB","url":"https://github.com/mattermost/mattermost/pull/36197"},{"type":"WEB","url":"https://github.com/mattermost/mattermost/pull/36377"},{"type":"WEB","url":"https://github.com/mattermost/mattermost/pull/36379"},{"type":"WEB","url":"https://github.com/mattermost/mattermost/pull/36380"},{"type":"WEB","url":"https://github.com/mattermost/mattermost/pull/36382"},{"type":"WEB","url":"https://github.com/mattermost/mattermost/commit/2c89c2f6768fbe4dfd57a21ca38c0aecead8d4a8"},{"type":"WEB","url":"https://github.com/mattermost/mattermost/commit/5e159647b16e571b327ac6882f32eae42971f540"},{"type":"WEB","url":"https://github.com/mattermost/mattermost/commit/8000e5933526f4fd66b92131db3a1b1f4520dbae"},{"type":"WEB","url":"https://github.com/mattermost/mattermost/commit/f0a390b96e4c730daedbaf5190684776730218c7"},{"type":"PACKAGE","url":"https://github.com/mattermost/mattermost"},{"type":"WEB","url":"https://github.com/mattermost/mattermost/releases/tag/v10.11.16"},{"type":"WEB","url":"https://github.com/mattermost/mattermost/releases/tag/v11.5.5"},{"type":"WEB","url":"https://github.com/mattermost/mattermost/releases/tag/v11.6.2"},{"type":"WEB","url":"https://github.com/mattermost/mattermost/releases/tag/v11.7.0"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-29T18:26:39.462492418Z"}}