{"action":"Upgrade github.com/mattermost/mattermost-server to 10.11.11+incompatible or later.","affected":[{"fixed":"10.11.11+incompatible","introduced":"10.11.0-rc1+incompatible"},{"fixed":"11.2.3+incompatible","introduced":"11.2.0-rc1+incompatible"},{"fixed":"11.3.1+incompatible","introduced":"11.3.0-rc1+incompatible"}],"component":"github.com/mattermost/mattermost-server","cve_ids":["CVE-2026-25783"],"ecosystem":"Go","epss":0.00296,"exploited":false,"fixed_versions":["10.11.11+incompatible","11.2.3+incompatible","11.3.1+incompatible"],"ghsa_id":"GHSA-2v3w-6g35-5f9v","id":"tcs_01M5KGFH7HMFZCXKGQKZ3MVG1E","modified_at":"2026-03-26T21:03:22.280226Z","published_at":"2026-03-26T20:33:02Z","references":["https://osv.dev/vulnerability/GO-2026-4725","https://github.com/advisories/GHSA-2v3w-6g35-5f9v","https://nvd.nist.gov/vuln/detail/CVE-2026-25783","https://github.com/mattermost/mattermost/commit/1346cf529aef0672c39a56ec10d1b8a9c8fb387d","https://mattermost.com/security-updates"],"severity":{"label":"medium","score":4.3},"sources":[{"source":"osv","source_id":"GO-2026-4725","url":"https://osv.dev/vulnerability/GO-2026-4725"},{"source":"nvd","source_id":"CVE-2026-25783","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-25783"}],"summary":"Mattermost fails to properly validate User-Agent header tokens in github.com/mattermost/mattermost-server"}