Introduction

The recent discovery of a directory traversal vulnerability in MJML version 4.18.0 is a pressing issue for system administrators and hosting providers. This flaw, identified as CVE-2025-67898, exposes web servers to significant risks. If you're responsible for managing a Linux server or a web application firewall, it's crucial to understand the implications and proactive measures necessary to mitigate this vulnerability.

Summary of the Incident

The vulnerability allows an attacker to exploit MJML's mj-include command, enabling filesystem access. This means that potential malware detection systems could fail to identify unauthorized file reads, particularly when dealing with CSS files. The root of this issue arises from an incomplete fix for a prior vulnerability, CVE-2020-12827. Such vulnerabilities can lead to brute-force attacks, making your server susceptible to more invasive threats.

Why This Matters for Server Admins and Hosting Providers

For system administrators and hosting providers, this finding underscores the vital importance of maintaining server security. Insecure configurations can lead to significant data breaches and loss of control over web applications. The ability of attackers to read files undetected poses a severe threat, making it imperative to implement stringent security practices.

Practical Tips for Mitigation

To protect your server infrastructure from threats associated with CVE-2025-67898, consider the following steps:

• Update MJML to the latest version that addresses the directory traversal vulnerabilities.
• Apply any available security patches immediately.
• Review and restrict file access permissions to only those necessary for system functionality.
• Implement a robust malware detection system to monitor suspicious activities.
• Utilize a web application firewall (WAF) to guard against potential exploitation attempts.

Now is the time to take action to ensure your server remains secure against evolving threats. Sign up for a free 7-day trial of BitNinja and see how it can proactively protect your infrastructure against vulnerabilities such as CVE-2025-67898.