CVE-2024-42406 Unauthorized access on archived channels

What is CVE-2024-42406?

CVE-2024-42406 is a medium-severity missing authorization vulnerability in Mattermost Mattermost Server, published on 26 Sep 2024. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

Mattermost versions 9.11.x <= 9.11.0, 9.10.x <= 9.10.1, 9.9.x <= 9.9.2 and 9.5.x <= 9.5.8 fail to properly authorize requests when viewing archived channels is disabled, which allows an attacker to retrieve post and file information about archived channels. Examples are flagged or unread posts as well as files.

Weakness: CWE-284

Which versions are affected by CVE-2024-42406?

1 open source package ship an affected version, including mattermost. It affects 1 product.

Products include Mattermost Mattermost Server.

How do I fix CVE-2024-42406?

Upgrade mattermost to a fixed version for your release line: 9.5.9, 9.9.3 or 9.10.2.

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

Is CVE-2024-42406 being exploited?

There is no known exploitation of CVE-2024-42406 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-2024-42406, GHSA-v53q-gwp7-274v.