CVE-2025-54525 Unexpected input to Create Channel Subscription endpoint causes DoS in Mattermost Confluence Plugin

What is CVE-2025-54525?

CVE-2025-54525 is a high-severity denial of service vulnerability in Mattermost Confluence Plugin, published on 11 Aug 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Mattermost Confluence Plugin version <1.5.0 fails to handle unexpected request body which allows attackers to crash the plugin via constant hit to create channel subscription endpoint with an invalid request body.

Weakness: CWE-1287

Which versions are affected by CVE-2025-54525?

3 open source packages ship an affected version, including github.com/mattermost/mattermost-plugin-confluence. It affects 1 product.

Products include Mattermost Confluence.

How do I fix CVE-2025-54525?

Upgrade github.com/mattermost/mattermost-plugin-confluence to 1.5.0 or later.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2025-54525 being exploited?

There is no known exploitation of CVE-2025-54525 in the wild and no public exploit code.

Other vulnerabilities in Mattermost Confluence Plugin

• CVE-2025-13523 Cross-Site Scripting (XSS) via Unescaped Display Names in Mattermost Confluence Plugin OAuth2 Flow High 7.7
• CVE-2025-52931 Unexpected input to Update Channel Subscription endpoint causes DoS in Mattermost Confluence Plugin High 7.5
• CVE-2025-44004 Unauthenticated Channel Subscription Creation in Mattermost Confluence Plugin High 7.2
• CVE-2025-54478 Unauthenticated Channel Subscription Edit in Mattermost Confluence Plugin High 7.2
• CVE-2025-48731 Unauthorized Subscription Edit to Confluence Space in Mattermost Confluence Plugin Medium 6.4

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-3cg3-3mmr-w8hj, GO-2025-3872.