{"action":"Upgrade github.com/mattermost/mattermost/server/v8 to 8.0.0-20251022210333-acda1fb5dd46 or later.","affected":[{"fixed":"8.0.0-20251022210333-acda1fb5dd46","introduced":"0"}],"component":"github.com/mattermost/mattermost/server/v8","cve_ids":["CVE-2025-12421"],"ecosystem":"Go","epss":0.00345,"exploited":false,"fixed_versions":["8.0.0-20251022210333-acda1fb5dd46"],"ghsa_id":"GHSA-mp6x-97xj-9x62","id":"tcs_01M5KFG2WSPAC7J2HB8B2Y2W1P","modified_at":"2025-12-15T21:11:10.008786Z","published_at":"2025-11-27T18:30:26Z","references":["https://osv.dev/vulnerability/GHSA-mp6x-97xj-9x62","https://nvd.nist.gov/vuln/detail/CVE-2025-12421","https://github.com/mattermost/mattermost/commit/5072bbf689a46b3b97b2373f26149f5891396e6b","https://github.com/mattermost/mattermost/commit/acda1fb5dd46a2f46c76ae67012423c760525eaa","https://github.com/mattermost/mattermost/commit/f361e7d75a7ab9df5a2106e1ceb919b94b55e41d","https://github.com/mattermost/mattermost/commit/feb598ed2b7ac3cb78a253b032ad7e4628b0de00","https://github.com/mattermost/mattermost","https://mattermost.com/security-updates"],"severity":{"label":"critical","score":9.9},"sources":[{"source":"osv","source_id":"GHSA-mp6x-97xj-9x62","url":"https://osv.dev/vulnerability/GHSA-mp6x-97xj-9x62"}],"summary":"Mattermost fails to to verify the token used during code exchange"}