Mattermost 10.11.x-10.11.21/11.7.x-11.7.6: OAuth Endpoints Unrestricted
CVE-2026-16045 Published on August 17, 2026
Delegated OAuth tokens could revoke unrelated OAuth application authorizations
Mattermost versions 11.7.x <= 11.7.6, 10.11.x <= 10.11.21 Mattermost failed to restrict OAuth deauthorization and personal access token management endpoints to direct user sessions, which allowed an OAuth app with a delegated user token to revoke the user's authorizations or tokens for other integrations via account-management endpoints.. Mattermost Advisory ID: MMSA-2026-00704
Vulnerability Analysis
CVE-2026-16045 can be exploited with network access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a small impact on availability.
Weakness Type
What is an AuthZ Vulnerability?
The software performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. This allows attackers to bypass intended access restrictions.
CVE-2026-16045 has been classified to as an AuthZ vulnerability or weakness.
Products Associated with CVE-2026-16045
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Affected Versions
Mattermost:- Version 11.7.0, <= 11.7.6 is affected.
- Version 10.11.0, <= 10.11.21 is affected.
- Version 11.9.0 is unaffected.
- Version 11.7.7 is unaffected.
- Version 10.11.22 is unaffected.