{"action":"Upgrade github.com/mattermost/mattermost-server to 5.3.2-0.20260129181235-1346cf529aef or later.","affected":[{"fixed":"5.3.2-0.20260129181235-1346cf529aef","introduced":"0"},{"fixed":"10.11.11","introduced":"10.11.0-rc1"},{"fixed":"11.2.3","introduced":"11.2.0-rc1"},{"fixed":"11.3.1","introduced":"11.3.0-rc1"}],"component":"github.com/mattermost/mattermost-server","cve_ids":["CVE-2026-25783"],"ecosystem":"Go","epss":0.00296,"exploited":false,"fixed_versions":["5.3.2-0.20260129181235-1346cf529aef","10.11.11","11.2.3","11.3.1"],"ghsa_id":"GHSA-2v3w-6g35-5f9v","id":"tcs_01M5KESN4PPK35297NK50J02FZ","modified_at":"2026-03-26T21:11:24.090883Z","published_at":"2026-03-16T15:30:42Z","references":["https://osv.dev/vulnerability/GHSA-2v3w-6g35-5f9v","https://nvd.nist.gov/vuln/detail/CVE-2026-25783","https://github.com/mattermost/mattermost/commit/1346cf529aef0672c39a56ec10d1b8a9c8fb387d","https://github.com/mattermost/mattermost","https://mattermost.com/security-updates"],"severity":{"label":"medium","score":4.3},"sources":[{"source":"osv","source_id":"GHSA-2v3w-6g35-5f9v#Go/github.com/mattermost/mattermost-server","url":"https://osv.dev/vulnerability/GHSA-2v3w-6g35-5f9v"}],"summary":"Mattermost fails to properly validate User-Agent header tokens"}