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.
Add your gear to cvedb and we'll alert you only when mattermost ships something exploited.
Check my exposure →This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.