{"action":"Upgrade github.com/mattermost/mattermost-server to 10.11.10+incompatible or later.","affected":[{"fixed":"10.11.10+incompatible","introduced":"10.11.0+incompatible"}],"component":"github.com/mattermost/mattermost-server","cve_ids":["CVE-2026-20796"],"ecosystem":"Go","epss":0.0022,"exploited":false,"fixed_versions":["10.11.10+incompatible"],"ghsa_id":"GHSA-2xf7-hmf6-p64j","id":"tcs_01M5KGE2TFGHG0GZ77RZDH98KV","modified_at":"2026-02-23T19:41:17.607287Z","published_at":"2026-02-23T18:23:12Z","references":["https://osv.dev/vulnerability/GO-2026-4495","https://github.com/advisories/GHSA-2xf7-hmf6-p64j","https://nvd.nist.gov/vuln/detail/CVE-2026-20796","https://mattermost.com/security-updates"],"severity":{"label":"low","score":3.1},"sources":[{"source":"osv","source_id":"GO-2026-4495","url":"https://osv.dev/vulnerability/GO-2026-4495"},{"source":"nvd","source_id":"CVE-2026-20796","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-20796"}],"summary":"Mattermost doesn't properly validate channel membership at the time of data retrieval in github.com/mattermost/mattermost-server"}