{"id":"GHSA-m2w9-h2mm-79qr","summary":"Mattermost doesn't require system-level permission when patching protected default system roles","details":"Mattermost versions 11.6.x \u003c= 11.6.1, 11.5.x \u003c= 11.5.4, 10.11.x \u003c= 10.11.15, 10.11.x \u003c= 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","aliases":["CVE-2026-6739","GO-2026-6285"],"modified":"2026-08-25T20:25:47.051334772Z","published":"2026-06-12T18:31:59Z","database_specific":{"github_reviewed":true,"github_reviewed_at":"2026-08-24T21:41:52Z","nvd_published_at":"2026-06-12T17:16:27Z","cwe_ids":["CWE-863"],"severity":"MODERATE"},"references":[{"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"},{"type":"WEB","url":"https://mattermost.com/security-updates"}],"affected":[{"package":{"name":"github.com/mattermost/mattermost-server","ecosystem":"Go","purl":"pkg:golang/github.com/mattermost/mattermost-server"},"ranges":[{"type":"SEMVER","events":[{"introduced":"11.6.0"},{"fixed":"11.6.1"}]}],"versions":["11.6.0"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-m2w9-h2mm-79qr/GHSA-m2w9-h2mm-79qr.json"}},{"package":{"name":"github.com/mattermost/mattermost-server","ecosystem":"Go","purl":"pkg:golang/github.com/mattermost/mattermost-server"},"ranges":[{"type":"SEMVER","events":[{"introduced":"11.5.0"},{"fixed":"11.5.5"}]}],"database_specific":{"last_known_affected_version_range":"\u003c= 11.5.4","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-m2w9-h2mm-79qr/GHSA-m2w9-h2mm-79qr.json"}},{"package":{"name":"github.com/mattermost/mattermost-server","ecosystem":"Go","purl":"pkg:golang/github.com/mattermost/mattermost-server"},"ranges":[{"type":"SEMVER","events":[{"introduced":"10.11.0"},{"fixed":"10.11.17"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-m2w9-h2mm-79qr/GHSA-m2w9-h2mm-79qr.json","last_known_affected_version_range":"\u003c= 10.11.15"}},{"package":{"name":"github.com/mattermost/mattermost/server/v8","ecosystem":"Go","purl":"pkg:golang/github.com/mattermost/mattermost/server/v8"},"ranges":[{"type":"SEMVER","events":[{"introduced":"8.0.0-20250731163400-5b955468ea1e"},{"fixed":"8.0.0-20260501142004-99b73d4c4acf"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-m2w9-h2mm-79qr/GHSA-m2w9-h2mm-79qr.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:L"}]}