CVE-2025-41443 Guest user can discover active public channels

What is CVE-2025-41443?

CVE-2025-41443 is a medium-severity missing authorization vulnerability in Mattermost Mattermost Server, published on 16 Oct 2025. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

Mattermost versions 10.5.x <= 10.5.12, 10.11.x <= 10.11.2 fail to properly validate guest user permissions when accessing channel information which allows guest users to discover active public channels and their metadata via the `/api/v4/teams/{team_id}/channels/ids` endpoint

Weakness: CWE-862

Which versions are affected by CVE-2025-41443?

7 open source packages ship an affected version, including github.com/mattermost/mattermost-server and github.com/mattermost/mattermost/server/v8. It affects 1 product.

Products include Mattermost Mattermost Server.

How do I fix CVE-2025-41443?

Upgrade github.com/mattermost/mattermost-server to a fixed version for your release line: 10.11.3 or 10.5.11.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2025-41443 being exploited?

There is no known exploitation of CVE-2025-41443 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-7cr3-38jm-6p45, GO-2025-4031.