Introduction to CVE-2025-11794

Recently, the cybersecurity landscape has witnessed a significant vulnerability—the CVE-2025-11794. This flaw impacts Mattermost versions, allowing unauthorized access to sensitive information like password hashes and MFA secrets. The issue arises from improper data sanitization in the email verification endpoint of the application.

What You Need to Know

This vulnerability affects Mattermost versions 10.11.x ≤ 10.11.3, 10.5.x ≤ 10.5.11, and 10.12.x ≤ 10.12.0. Insecure endpoints can expose critical user data, which can be exploited by malicious actors. Such breaches can lead to brute-force attacks, putting user accounts at severe risk. For system administrators and hosting providers, this is a wake-up call to enhance server protections.

Why This Matters

As a system administrator or a hosting provider, understanding this vulnerability is crucial. Your Linux server could be at risk, compromising not only its integrity but also the data of every user. The potential for automated brute-force attacks increases when unauthorized access to sensitive information is possible.

Practical Mitigation Steps

To protect your infrastructure from CVE-2025-11794, consider the following actions:

• Update Mattermost: Ensure that you are running the latest version that addresses this vulnerability.
• Implement a Web Application Firewall: Use a web application firewall (WAF) to filter and monitor HTTP traffic to and from your server.
• Enhance User Data Sanitization: Regularly review and improve your sanitization processes for user data.
• Monitor for Cybersecurity Alerts: Set up alerts for any unusual activity that could indicate a brute-force attack.