CVE-2025-53971 - CVE House
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Status published Low CVE-2025-53971

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

Vulnerability 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.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

The following person or organization is credited with identifying this vulnerability, as recorded in the NVD database:

  • hackit_bharat

References

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Affected Vendor

Affected Software

Mattermost
Vulnerable Versions:
10.5.0, 9.11.0, 10.10.0, 10.5.9, 9.11.18

Timeline

Official Publish: August 21st, 2025
Last Modified: August 21st, 2025
Added to House: July 22nd, 2026

CVSS Vectors

V3: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N

Weaknesses (CWE)

CWE-863

MITRE ATT&CK TTPs

T1190 Exploit Public-Facing Application
Initial Access
T1078 Valid Accounts
Persistence
T1548 Abuse Elevation Control Mechanism
Privilege Escalation
T1021 Remote Services
Lateral Movement
T1098 Account Manipulation
Defense Evasion