CVE-2026-3113 mmctl export download command doesn’t restrict permissions to created file to file owner

What is CVE-2026-3113?

CVE-2026-3113 is a medium-severity vulnerability in Mattermost Mattermost Server, published on 26 Mar 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

Official description

Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to set permissions on downloaded bulk export which allows other local users on the server to be able to read contents of the bulk export.. Mattermost Advisory ID: MMSA-2026-00593

Weakness: CWE-732

Which versions are affected by CVE-2026-3113?

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

Products include Mattermost Mattermost Server.

How do I fix CVE-2026-3113?

Upgrade github.com/mattermost/mattermost-server to a fixed version for your release line: 10.11.12, 10.11.12+incompatible, 11.2.4+incompatible or 11.3.2+incompatible.

Is CVE-2026-3113 being exploited?

There is no known exploitation of CVE-2026-3113 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-4765-v66x-rqx7, GO-2026-5112.