{"action":"Upgrade github.com/mattermost/mattermost/server/v8 to 8.0.0-20260130144323-5bb5261c72fa or later.","affected":[{"fixed":"8.0.0-20260130144323-5bb5261c72fa","introduced":"0"}],"component":"github.com/mattermost/mattermost/server/v8","cve_ids":["CVE-2026-21386"],"ecosystem":"Go","epss":0.00187,"exploited":false,"fixed_versions":["8.0.0-20260130144323-5bb5261c72fa"],"ghsa_id":"GHSA-5mr9-crcg-8wh2","id":"tcs_01M5KGFSDD9JX46514H0XJ3PSV","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":"unknown"},"sources":[{"source":"osv","source_id":"GO-2026-4744#Go/github.com/mattermost/mattermost/server/v8","url":"https://osv.dev/vulnerability/GO-2026-4744"}],"summary":"Mattermost fails to use consistent error responses when handling the /mute command in github.com/mattermost/mattermost-server"}