CVE-2025-9072 One-Click Mattermost Account Takeover via Poisoned RelayState SAML Parameter

What is CVE-2025-9072?

CVE-2025-9072 is a high-severity vulnerability in Mattermost Mattermost Server, published on 15 Sep 2025. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

Official description

Mattermost versions 10.10.x <= 10.10.1, 10.5.x <= 10.5.9, 10.9.x <= 10.9.4 fail to validate the redirect_to parameter, allowing an attacker to craft a malicious link that, once a user authenticates with their SAML provider, could post the user’s cookies to an attacker-controlled URL.

Weakness: CWE-601

Which versions are affected by CVE-2025-9072?

12 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-2025-9072?

Upgrade github.com/mattermost/mattermost-server to a fixed version for your release line: 10.10.2, 10.5.10, 10.5.10+incompatible or 10.9.5+incompatible.

Is CVE-2025-9072 being exploited?

There is no known exploitation of CVE-2025-9072 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-69j8-prx2-vx98, GO-2025-3958.