{"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-2026-21386"],"ecosystem":"Go","epss":0.00187,"exploited":false,"fixed_versions":["10.11.11+incompatible","11.2.3+incompatible","11.3.1+incompatible"],"ghsa_id":"GHSA-5mr9-crcg-8wh2","id":"tcs_01M5KGFRTJJJP00S1K4KTP82BB","modified_at":"2026-03-23T18:45:19.760351Z","published_at":"2026-03-23T18:14:47Z","references":["https://osv.dev/vulnerability/GO-2026-4744","https://github.com/advisories/GHSA-5mr9-crcg-8wh2","https://nvd.nist.gov/vuln/detail/CVE-2026-21386","https://github.com/mattermost/mattermost/commit/5bb5261c72faa476558a694c23581d24b734da41","https://mattermost.com/security-updates"],"severity":{"label":"medium","score":4.3},"sources":[{"source":"osv","source_id":"GO-2026-4744","url":"https://osv.dev/vulnerability/GO-2026-4744"},{"source":"nvd","source_id":"CVE-2026-21386","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-21386"}],"summary":"Mattermost fails to use consistent error responses when handling the /mute command in github.com/mattermost/mattermost-server"}