CVE-2025-53971

Channel and Team Membership APIs inadvertently allow loss of Member privileges.

Published Aug 21, 2025 CVSS 3.1 · 3.8 Low EPSS < 1% KEV · Not listed
Description
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.

Remediation

Vendor Solution

Update Mattermost to versions 10.10.0, 10.5.9, 9.11.18 or higher.

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2025-25413 Mattermost Fails to Properly Validate Team Role Modification
Github GHSA Github GHSA GHSA-4276-cm8c-788h Mattermost Fails to Properly Validate Team Role Modification
References
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Mattermost
Mattermost mattermost
Vendors & Products Mattermost
Mattermost mattermost
Type Values Removed Values Added
Description 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.
Title Channel and Team Membership APIs inadvertently allow loss of Member privileges.
Weaknesses CWE-863
References
Metrics cvssV3_1

{'score': 3.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Mattermost
Published
Updated
Aug 21, 2025, 2:51 PM
Reserved
Jul 22, 2025, 7:46 AM
Status
Analyzed
Published
Aug 21, 2025, 8:15 AM
Modified
Jun 17, 2026, 9:39 AM