{"id":"CVE-2026-3433","aliases":["GHSA-rp4v-qc77-phm4"],"url":"https://o3.security/vulnerability/CVE-2026-3433","summary":"Mattermost fails to scope role_updated websocket events to authorized team and channel members","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 restrict role_updated websocket event broadcasts to members of the affected team or channel which allows an authenticated attacker with guest-level access to observe permission scheme change notifications for private teams they are not a member of via the websocket connection.. Mattermost Advisory ID: MMSA-2026-00616","published":"2026-06-12T15:46:54.868Z","modified":"2026-09-29T18:26:39.766780680Z","cvss":{"score":4.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N"},"epss":{"score":0.0018,"percentile":0.07897,"asOf":"2026-09-17"},"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":"8.0.0-20260504071740-9408b98025d7"}],"fix":{"url":"https://github.com/mattermost/mattermost/pull/35497","label":"mattermost/mattermost#35497"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3433.json"},{"type":"ADVISORY","url":"https://mattermost.com/security-updates"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-3433"},{"type":"WEB","url":"https://github.com/mattermost/mattermost/pull/35497"},{"type":"WEB","url":"https://github.com/mattermost/mattermost/pull/36256"},{"type":"WEB","url":"https://github.com/mattermost/mattermost/pull/36257"},{"type":"WEB","url":"https://github.com/mattermost/mattermost/pull/36341"},{"type":"WEB","url":"https://github.com/mattermost/mattermost/commit/0a0ab0d54d899d308bd1352cc577036917500318"},{"type":"WEB","url":"https://github.com/mattermost/mattermost/commit/7425c6817bf244f976c729f8a73cecac8039a1e1"},{"type":"WEB","url":"https://github.com/mattermost/mattermost/commit/9408b98025d7364d7dfe7cdb28fcd109b1b595a6"},{"type":"WEB","url":"https://github.com/mattermost/mattermost/commit/a30a331a29b9766d46716d4252056d7b74e66da0"},{"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":"2026-09-29T18:26:39.766780680Z"}}