CVE-2026-16045
Received Received - Intake

OAuth Token Revocation Bypass in Mattermost

Publication date: 2026-08-17

Last updated on: 2026-08-17

Assigner: Mattermost, Inc.

Description
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

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Meta Information

Published
2026-08-17
Last Modified
2026-08-17
Generated
2026-08-17
AI Q&A
2026-08-17
EPSS Evaluated
N/A
NVD
CVE-2026-16045
EUVD
EUVD-2026-60210

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
mattermost mattermost to 11.7.6 (inc)
mattermost mattermost to 10.11.21 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-863 The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

Attack-Flow Graph

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Executive Summary

Mattermost versions between 11.7.0 and 11.7.6, and 10.11.0 and 10.11.21 have a flaw where OAuth deauthorization and personal access token management endpoints were not properly restricted to direct user sessions. This allowed an OAuth app with a delegated user token to revoke authorizations or tokens for other integrations via account-management endpoints.

Detection Guidance

Check Mattermost server logs for unauthorized OAuth deauthorization or personal access token revocation events. Review API access logs for suspicious activity targeting account-management endpoints.

Impact Analysis

An attacker with access to a delegated user token could revoke your authorizations or tokens for other integrations, disrupting your access to connected services or applications.

Compliance Impact

This vulnerability could potentially impact compliance with GDPR and HIPAA by allowing unauthorized revocation of user authorizations or tokens. This may lead to unauthorized access or loss of access controls, which are critical for maintaining data protection and integrity under these regulations.

Mitigation Strategies

Upgrade Mattermost to a patched version (11.7.7 or later, 10.11.22 or later). Review and revoke any potentially compromised OAuth tokens or personal access tokens. Monitor account-management endpoints for unusual activity.

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