An incorrect authorization flaw in Mattermost allows authenticated attackers to perform unauthorized actions, potentially leading to full system impact.

This is an incorrect authorization vulnerability (CWE-863) that occurs when a low-privileged authenticated user can bypass intended access controls. The flaw permits unauthorized operations that should be restricted to administrative or higher-level roles.

Successful exploitation allows an authenticated user to perform actions outside their assigned permissions, which could lead to the compromise of confidential communications or unauthorized modification of system data. With a CVSS score of 8.3, the risk of privilege escalation and data integrity loss is substantial for enterprise collaboration environments.

Immediate Action: Update Mattermost to versions 11.9.0, 11.7.7, 10.11.22, or 11.8.4 or higher to resolve the authorization logic errors.

Proactive Monitoring: Monitor audit logs for suspicious administrative actions performed by standard user accounts or unexpected changes to channel and team permissions.

Compensating Controls: Implement strict role-based access control (RBAC) policies and limit the number of users with high-level privileges until the environment is patched.

Public Exploit Available: Unknown

Organizations utilizing Mattermost must prioritize these updates to maintain the integrity of their collaboration platforms. Applying the vendor-provided patches is the only reliable method to remediate this authorization bypass.