CVE-2025-9084 Open redirect in OAuth login

What is CVE-2025-9084?

CVE-2025-9084 is a low-severity vulnerability in Mattermost Mattermost Server, published on 15 Sep 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

Mattermost versions 10.5.x <= 10.5.9 fail to properly validate redirect URLs which allows attackers to redirect users to malicious sites via crafted OAuth login URLs

Weakness: CWE-601

Which versions are affected by CVE-2025-9084?

8 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-2025-9084?

Upgrade github.com/mattermost/mattermost-server to a fixed version for your release line: 10.5.10 or 10.5.10+incompatible.

Is CVE-2025-9084 being exploited?

There is no known exploitation of CVE-2025-9084 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-hm95-jx66-g2gh, GO-2025-3960.