Mattermost Team Creation Priv Escalation 10.11-11.6
CVE-2026-6689 Published on June 12, 2026
*Missing* {{invite_user}} *permission check on team creation allows unprivileged users to set open-invite and allowed-domains team settings*
Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 Fail to enforce PermissionInviteUser when setting AllowOpenInvite or AllowedDomains during team creation (the check was only applied on update/patch), which allows an authenticated user holding PermissionCreateTeam but not PermissionInviteUser on the resulting team to configure invite-controlled team settings (make the team publicly joinable via open invite and/or constrain membership via allowed domains) that they are not permitted to set on an existing team via POST /api/v4/teams with allow_open_invite: true and/or a non-empty allowed_domains in the request body.. Mattermost Advisory ID: MMSA-2026-00655
Vulnerability Analysis
CVE-2026-6689 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, with no impact on integrity, and no impact on availability.
Weakness Type
What is an AuthZ Vulnerability?
The software does not perform an authorization check when an actor attempts to access a resource or perform an action.
CVE-2026-6689 has been classified to as an AuthZ vulnerability or weakness.
Products Associated with CVE-2026-6689
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Affected Versions
Mattermost:- Version 11.6.0, <= 11.6.1 is affected.
- Version 11.5.0, <= 11.5.4 is affected.
- Version 10.11.0, <= 10.11.15 is affected.
- Version 10.11.0, <= 10.11.16 is affected.
- Version 11.7.0 is unaffected.
- Version 11.6.2 is unaffected.
- Version 11.5.5 is unaffected.
- Version 10.11.16 is unaffected.
- Version 10.11.17 is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.