CVE-2026-7184 Mattermost Remote Cluster PATCH API Leaks Authentication Tokens

What is CVE-2026-7184?

CVE-2026-7184 is a medium-severity vulnerability in Mattermost Mattermost Server, published on 12 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15 fail to sanitize the Remote Cluster API response on PATCH operations, which allows authenticated users with the {{manage_secure_connections}} permission to obtain remote cluster authentication tokens via a PATCH request to the remote cluster endpoint.. Mattermost Advisory ID: MMSA-2026-00662

Weakness: CWE-201

Which versions are affected by CVE-2026-7184?

12 open source packages ship an affected version, including github.com/mattermost/mattermost-server, github.com/mattermost/mattermost-server/v5 and github.com/mattermost/mattermost-server/v6. It affects 1 product.

Products include Mattermost Mattermost Server.

How do I fix CVE-2026-7184?

Upgrade github.com/mattermost/mattermost-server to a fixed version for your release line: 10.11.16, 10.11.16+incompatible, 11.5.5+incompatible or 11.6.1+incompatible.

Is CVE-2026-7184 being exploited?

There is no known exploitation of CVE-2026-7184 in the wild and no public exploit code.

Other vulnerabilities in Mattermost Mattermost Server

• CVE-2025-12419 Account takeover on OAuth/OpenID-enabled servers Critical 9.9
• CVE-2025-12421 Account Takeover via Code Exchange Endpoint Critical 9.9
• CVE-2025-4981 Path Traversal Leading to RCE by Any Authenticated Mattermost User Critical 9.9
• CVE-2025-20051 Arbitrary file read via block duplication in Mattermost Boards Critical 9.9
• CVE-2025-25279 Arbitrary file read in Mattermost Boards via import & export board archive Critical 9.9

All Mattermost Mattermost Server vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-9p44-r552-4wp9, GO-2026-6282.