CVE-2023-6459 Public endpoint /metrics of Calls plugin reveals channel IDs

What is CVE-2023-6459?

CVE-2023-6459 is a medium-severity vulnerability in Mattermost Mattermost Server, published on 6 Dec 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Mattermost is grouping calls in the /metrics endpoint by id and reports that id in the response. Since this id is the channelID, the public /metrics endpoint is revealing channelIDs.

Weakness: CWE-200

Which versions are affected by CVE-2023-6459?

5 open source packages ship an affected version, including github.com/mattermost/mattermost-server/v6, mattermost and github.com/mattermost/mattermost/server/v8. It affects 1 product.

Products include Mattermost Mattermost Server.

How do I fix CVE-2023-6459?

Upgrade github.com/mattermost/mattermost-server/v6 to 7.8.14 or later.

Is CVE-2023-6459 being exploited?

There is no known exploitation of CVE-2023-6459 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 BIT-mattermost-2023-6459, GHSA-63cv-4pc2-4fcf.