{"id":"GHSA-mxq2-5jpg-7474","summary":"Mattermost doesn't validate channel ownership of an existing subscription before applying edits","details":"Mattermost versions 11.7.x \u003c= 11.7.0, 11.6.x \u003c= 11.6.2, 11.5.x \u003c= 11.5.5, 10.11.x \u003c= 10.11.17 Fail to validate channel ownership of an existing subscription before applying edits which allows an authenticated attacker to hijack subscriptions from channels they have no access to via a crafted PUT request to the subscription edit endpoint.. Mattermost Advisory ID: MMSA-2026-00650","aliases":["CVE-2026-6062","GO-2026-6484"],"modified":"2026-09-28T17:10:50.339898669Z","published":"2026-06-22T15:30:45Z","database_specific":{"github_reviewed_at":"2026-09-15T19:50:42Z","nvd_published_at":"2026-06-22T14:17:51Z","cwe_ids":["CWE-639"],"severity":"MODERATE","github_reviewed":true},"references":[{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-6062"},{"type":"PACKAGE","url":"https://github.com/mattermost/mattermost"},{"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":"11.7.0"},{"fixed":"11.7.1"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-mxq2-5jpg-7474/GHSA-mxq2-5jpg-7474.json"}},{"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":"11.6.3"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-mxq2-5jpg-7474/GHSA-mxq2-5jpg-7474.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":"11.5.6"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-mxq2-5jpg-7474/GHSA-mxq2-5jpg-7474.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":"10.11.18"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-mxq2-5jpg-7474/GHSA-mxq2-5jpg-7474.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L"}]}