{"action":"Upgrade github.com/mattermost/mattermost/server/v8 to 8.0.0-20250723052842-4cb8d8940332 or later.","affected":[{"fixed":"8.0.0-20250723052842-4cb8d8940332","introduced":"8.0.0-20250721062209-4952acea88ce"}],"component":"github.com/mattermost/mattermost/server/v8","cve_ids":["CVE-2026-3590"],"ecosystem":"Go","epss":0.0023,"exploited":false,"fixed_versions":["8.0.0-20250723052842-4cb8d8940332"],"ghsa_id":"GHSA-mh4x-rmrx-3hp4","id":"tcs_01M5KFFWWTAPXMQHX2KT2D5E9Q","modified_at":"2026-06-25T23:11:44.105865703Z","published_at":"2026-04-17T15:31:17Z","references":["https://osv.dev/vulnerability/GHSA-mh4x-rmrx-3hp4","https://nvd.nist.gov/vuln/detail/CVE-2026-3590","https://github.com/mattermost/mattermost","https://mattermost.com/security-updates"],"severity":{"label":"medium","score":6.5},"sources":[{"source":"osv","source_id":"GHSA-mh4x-rmrx-3hp4","url":"https://osv.dev/vulnerability/GHSA-mh4x-rmrx-3hp4"}],"summary":"Mattermost has session spoofing due to lack of single-use consumption of guest magic link tokens enforcement"}