{"action":"Upgrade github.com/mattermost/mattermost/server/v8 to 10.11.11 or later.","affected":[{"fixed":"11.4.1","introduced":"11.4.0-rc1"},{"fixed":"11.3.2","introduced":"11.3.0-rc1"},{"fixed":"11.2.3","introduced":"11.2.0-rc1"},{"fixed":"10.11.11","introduced":"10.11.0-rc1"},{"fixed":"10.11.11","introduced":"8.0.0-20260105080200-d27a2195068d"}],"component":"github.com/mattermost/mattermost/server/v8","cve_ids":["CVE-2026-27659"],"ecosystem":"Go","epss":0.00125,"exploited":false,"fixed_versions":["11.4.1","11.3.2","11.2.3","10.11.11"],"ghsa_id":"GHSA-rmhw-c3xr-m3xx","id":"tcs_01M5KFMY2TTZ9A1QC8FWY6E7DE","modified_at":"2026-06-25T23:11:25.847160889Z","published_at":"2026-03-25T18:31:53Z","references":["https://osv.dev/vulnerability/GHSA-rmhw-c3xr-m3xx","https://nvd.nist.gov/vuln/detail/CVE-2026-27659","https://github.com/mattermost/mattermost","https://mattermost.com/security-updates"],"severity":{"label":"medium","score":4.6},"sources":[{"source":"osv","source_id":"GHSA-rmhw-c3xr-m3xx","url":"https://osv.dev/vulnerability/GHSA-rmhw-c3xr-m3xx"}],"summary":"Mattermost doesn't properly validate CSRF tokens"}