{"action":"Upgrade github.com/mattermost/mattermost-server to 11.5.2+incompatible or later.","affected":[{"fixed":"11.5.2+incompatible","introduced":"11.5.0+incompatible"}],"component":"github.com/mattermost/mattermost-server","cve_ids":["CVE-2026-5163"],"ecosystem":"Go","epss":0.00205,"exploited":false,"fixed_versions":["11.5.2+incompatible"],"ghsa_id":"GHSA-8r89-8w26-cq32","id":"tcs_01M5KGK2P18PB1KRX8KVC2MN8G","modified_at":"2026-06-25T19:45:24.915964531Z","published_at":"2026-06-25T18:43:15Z","references":["https://osv.dev/vulnerability/GO-2026-5263","https://github.com/advisories/GHSA-8r89-8w26-cq32","https://nvd.nist.gov/vuln/detail/CVE-2026-5163","https://github.com/mattermost/mattermost/commit/f4d1abe7e8f545f1a87f463fa9fe451c731aebf8","https://mattermost.com/security-updates"],"severity":{"label":"unknown"},"sources":[{"source":"osv","source_id":"GO-2026-5263","url":"https://osv.dev/vulnerability/GO-2026-5263"}],"summary":"Mattermost doesn't verify channel membership when processing AI-assisted message rewrites in github.com/mattermost/mattermost-server"}