CVE-2026-6689 Details
Description
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
A vulnerability exists in Mattermost versions 11.6.x through 11.6.1, 11.5.x through 11.5.4, and 10.11.x through 10.11.16. The issue arises because these versions do not properly enforce the PermissionInviteUser setting when AllowOpenInvite or AllowedDomains are configured during team creation. As a result, an authenticated user with PermissionCreateTeam but without PermissionInviteUser can manipulate invite-related team settings, such as making a team publicly joinable or restricting membership through allowed domains, in ways they are not authorized to on an existing team.
Users can upgrade to Mattermost versions 11.7.0, 11.8.0, or 11.7.0 to address this vulnerability.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jun 12, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://mattermost.com/security-updates | [email protected] | Vendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-862 | Missing Authorization | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| mattermost mattermost server | >= 10.11.0, < 10.11.17 >= 11.5.0, < 11.5.5 >= 11.6.0, < 11.6.2 |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 18, 2026 | Initial Analysis | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Jun 12, 2026 | New CVE Received | [email protected] |