{"id":"CVE-2026-16453","published":"2026-10-16T08:17:12.640","lastModified":"2026-10-16T19:23:18.623","description":"Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to verify the integrity of the SAML RelayState POST parameter which allows an authenticated SAML user to join any team, including invite-only teams, via forging the team_id or invite_id fields in the RelayState.. Mattermost Advisory ID: MMSA-2026-00727","cvssScore":7.1,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N","cwes":["CWE-472"],"vendors":[],"products":[],"references":[{"url":"https://mattermost.com/security-updates","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}