Mattermost 11.7.0: Admin can downgrade bots via demoteuser API
CVE-2026-8823 Published on June 22, 2026
User Manager can demote bot accounts to guest without bot-management permission
Mattermost versions 11.7.x <= 11.7.0, 10.11.x <= 10.11.17 fail to validate bot targets when demoting users to guests which allows a lower-privileged administrator to degrade arbitrary bot accounts via the standard demote-user API.. Mattermost Advisory ID: MMSA-2026-00669
Vulnerability Analysis
CVE-2026-8823 can be exploited with network access, and requires 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, with no impact on integrity and 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-2026-8823 has been classified to as an AuthZ vulnerability or weakness.
Products Associated with CVE-2026-8823
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Affected Versions
Mattermost:- Version 11.7.0, <= 11.7.0 is affected.
- Version 10.11.0, <= 10.11.17 is affected.
- Version 11.8.0 is unaffected.
- Version 11.7.1 is unaffected.
- Version 10.11.18 is unaffected.