Mattermost 11.9.0 channel action ownership validation flaw
CVE-2026-10542 Published on September 14, 2026
Playbooks channel action update validation issue
Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to validate channel action ownership which allows channel managers to update actions in other channels via the channel action update endpoint.. Mattermost Advisory ID: MMSA-2026-00692
Vulnerability Analysis
CVE-2026-10542 is exploitable with network access, and requires small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to be low. considered to have a small impact on confidentiality and integrity and availability.
Weakness Type
What is an Insecure Direct Object Reference / IDOR Vulnerability?
The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.
CVE-2026-10542 has been classified to as an Insecure Direct Object Reference / IDOR vulnerability or weakness.
Products Associated with CVE-2026-10542
Want to know whenever a new CVE is published for MatterMost? stack.watch will email you.
Affected Versions
Mattermost:- Version 11.9.0, <= 11.9.0 is affected.
- Version 11.8.0, <= 11.8.4 is affected.
- Version 11.7.0, <= 11.7.7 is affected.
- Version 10.11.0, <= 10.11.22 is affected.
- Version 11.10.0 is unaffected.
- Version 11.9.1 is unaffected.
- Version 11.8.5 is unaffected.
- Version 11.7.8 is unaffected.
- Version 10.11.23 is unaffected.