{"action":"Upgrade github.com/mattermost/mattermost-server to 5.3.2-0.20251212052346-61651b0df7ea or later.","affected":[{"introduced":"11.1.0"},{"introduced":"10.11.0"},{"introduced":"11.2.0"},{"fixed":"5.3.2-0.20251212052346-61651b0df7ea","introduced":"0"}],"component":"github.com/mattermost/mattermost-server","cve_ids":["CVE-2026-0999"],"ecosystem":"Go","epss":0.002,"exploited":false,"fixed_versions":["5.3.2-0.20251212052346-61651b0df7ea"],"ghsa_id":"GHSA-3c9r-7f29-qp32","id":"tcs_01M5KETJWAYZAK71G400AFMMV2","modified_at":"2026-04-01T17:34:48.742132Z","published_at":"2026-02-16T12:30:24Z","references":["https://osv.dev/vulnerability/GHSA-3c9r-7f29-qp32","https://nvd.nist.gov/vuln/detail/CVE-2026-0999","https://github.com/mattermost/mattermost/commit/61651b0df7ea5db55d1e54f8d6fb5fce4149309c","https://github.com/mattermost/mattermost","https://mattermost.com/security-updates"],"severity":{"label":"medium","score":5.4},"sources":[{"source":"osv","source_id":"GHSA-3c9r-7f29-qp32#Go/github.com/mattermost/mattermost-server","url":"https://osv.dev/vulnerability/GHSA-3c9r-7f29-qp32"}],"summary":"Mattermost fails to properly validate login method restrictions"}