{"action":"No fix published. Pin and monitor.","affected":[{"introduced":"0"}],"component":"github.com/mattermost/mattermost-server/v6","cve_ids":["CVE-2025-13821"],"ecosystem":"Go","epss":0.00238,"exploited":false,"fixed_versions":[],"ghsa_id":"GHSA-pp9j-pf5c-659x","id":"tcs_01M5KGE9NJ0KH4KXSYESA8NGM5","modified_at":"2026-02-23T19:41:19.495726Z","published_at":"2026-02-23T18:23:12Z","references":["https://osv.dev/vulnerability/GO-2026-4524","https://github.com/advisories/GHSA-pp9j-pf5c-659x","https://nvd.nist.gov/vuln/detail/CVE-2025-13821","https://github.com/mattermost/mattermost/commit/cd17b61de41bf0a49b524bb91ce0bbe859e5a100","https://mattermost.com/security-updates"],"severity":{"label":"medium","score":5.7},"sources":[{"source":"osv","source_id":"GO-2026-4524#Go/github.com/mattermost/mattermost-server/v6","url":"https://osv.dev/vulnerability/GO-2026-4524"},{"source":"nvd","source_id":"CVE-2025-13821","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-13821"}],"summary":"Mattermost fails to sanitize sensitive data in WebSocket messages in github.com/mattermost/mattermost-server"}