Headline
GHSA-4276-cm8c-788h: Mattermost Fails to Properly Validate Team Role Modification
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.
- GitHub Advisory Database
- GitHub Reviewed
- CVE-2025-53971
Mattermost Fails to Properly Validate Team Role Modification
Low severity GitHub Reviewed Published Aug 21, 2025 to the GitHub Advisory Database • Updated Aug 21, 2025
Package
gomod github.com/mattermost/mattermost-server (Go)
Affected versions
>= 10.5.0, <= 10.5.8
>= 9.11.0, <= 9.11.17
Patched versions
10.5.9
9.11.18
gomod github.com/mattermost/mattermost/server/v8 (Go)
< 8.0.0-20250721095846-c602a4a78e1f
8.0.0-20250721095846-c602a4a78e1f
Published to the GitHub Advisory Database
Aug 21, 2025
Last updated
Aug 21, 2025