CVE-2026-6689
Mattermost doesn't enforce PermissionInviteUser when setting AllowOpenInvite or AllowedDomains during team creation
Summary
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
Affected packages
| Ecosystem | Package | Affected versions | Fixed versions |
|---|---|---|---|
| Go | github.com/mattermost/mattermost-server | — | 11.6.1, 11.5.5, 10.11.17 |
| Go | github.com/mattermost/mattermost/server/v8 | — | 8.0.0-20260501144115-7d6816abdfd1 |
Remediation: Upgrade to 11.6.1 or later.
References
Includes data from the GitHub Advisory Database, licensed under CC-BY 4.0.
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EPSS scores provided by the FIRST.org Exploit Prediction Scoring System.