CVE-2025-53971

Mattermost versions 10.5.x = 10.5.8, 9.11.x = 9.11.17 fail to properly validate authorization for team scheme role modifications which allows Team Admins to demote Team Members to Guests via the PUT /api/v4/teams/team-id/members/user-id/schemeRoles API endpoint...

CVE-2025-53971

Mattermost Server vulnerability CVE-2025-53971 affects versions 10.5.x ≤ 10.5.8 and 9.11.x ≤ 9.11.17. The issue arises from improper authorization validation for team scheme role modifications, allowing Team Admins to demote Team Members to Guests via PUT /api/v4/teams/{team-id}/members/{user-id}...

CVE-2024-4195

Mattermost versions 9.6.0, 9.5.x before 9.5.3, and 8.1.x before 8.1.12 fail to fully validate role changes, which allows an attacker authenticated as a team admin to promote guests to team admins via crafted HTTP requests...