CVSS 7.1 (high) · published 2026-10-16
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
Affected products (NVD): mattermost mattermost_server
Fixed in (NVD): 11.7.10, 11.8.6, 11.9.2
Weakness: CWE-472
Source: NVD CVE-2026-16453
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