How to Fix CVE-2025-24813: Path Equivalence Vulnerability in Apache Tomcat?

Apache Tomcat, a widely used open-source web server and servlet container, has been found to have a path equivalence vulnerability that could be exploited to achieve remote code execution. This flaw, identified as CVE-2025-24813, arises from improper handling of paths containing internal dots, potentially leading to serious security compromises, including viewing sensitive files, content injection, and in specific configurations, remote code execution.

Security professionals working in DevSecOps, application security, product security, vulnerability management, penetration testing, red teams, security operations, and engineering teams need to understand the details of this vulnerability and apply the necessary mitigations to protect their applications and systems. This article provides a comprehensive overview of CVE-2025-24813, including its description, impact, affected versions, and remediation steps, enabling you to secure your Apache Tomcat deployments effectively.

A Short Introduction to Apache Tomcat

Apache Tomcat is an open-source implementation of the Java Servlet, JavaServer Pages (JSP), Java Expression Language, and WebSocket specifications. It provides a "pure Java" HTTP web server environment in which Java code can run. Tomcat is widely used to deploy web applications and is a popular choice for both development and production environments due to its flexibility, scalability, and robust feature set. Its role as a central component in many web application architectures makes securing Tomcat deployments a critical task.

Summary of CVE-2025-24813

CVE-2025-24813 is a path equivalence vulnerability that stems from the way Apache Tomcat handles paths containing internal dots (e.g., file.name). This improper handling can be exploited under specific conditions, potentially leading to the viewing of security-sensitive files, the injection of malicious content into files, or even remote code execution. For more information, refer to the NVD entry for CVE-2025-24813.

The vulnerability is triggered due to the default servlet not correctly sanitizing or validating file paths when writes are enabled, partial PUT support is active, and specific URL configurations are in place. An attacker with knowledge of the target file names can leverage this flaw to manipulate files in unexpected ways.

The most severe outcome, remote code execution, is possible if the application is using Tomcat's file-based session persistence with the default storage location and includes a library vulnerable to deserialization attacks. This combination of factors creates a pathway for attackers to execute arbitrary code on the server.

Impact of the Vulnerabilities

The exploitation of CVE-2025-24813 can have significant repercussions for affected systems. Under the right circumstances, attackers could leverage this vulnerability to:

It is important to note that the exploitation of this vulnerability requires multiple specific conditions to be met:

Products Affected by the Vulnerabilities

The following Apache Tomcat versions are affected by CVE-2025-24813:

How to Check Your Product is Vulnerable?

To determine if your Apache Tomcat installation is vulnerable to CVE-2025-24813, you can follow these steps:

1. Check Tomcat Version: The most straightforward method is to check the version of your Apache Tomcat installation. You can typically find this information in the Tomcat administration interface or by running the version.sh (or version.bat on Windows) script located in the Tomcat bin directory.

2. Review web.xml Configuration: Examine the web.xml file in your Tomcat configuration directory (conf/web.xml). Look for the configuration of the default servlet.

* Check if the readonly parameter is set to false, which would enable writes to the default servlet.

* Verify whether partial PUT support is enabled.

3. Analyze URL Configurations: Review your application's URL configurations to identify any potential target URLs for security-sensitive uploads that are sub-directories of target URLs for public uploads.

4. Assess Deserialization Risks: Evaluate your application for any libraries that might be leveraged in deserialization attacks, especially if you are using Tomcat's file-based session persistence with the default storage location.

5. Check Default Servlet settings: Verify default servlet settings are restrictive

6. Monitor and Validate File Upload and Storage Mechanisms: Validate file upload and storage mechanisms

How to Fix the Vulnerabilities?

The primary remediation strategy for CVE-2025-24813 is to upgrade to a patched version of Apache Tomcat. Here are the recommended steps:

1. Upgrade Tomcat: Upgrade your Apache Tomcat installation to one of the following fixed versions:

* Apache Tomcat 11.0.3 or later

* Apache Tomcat 10.1.35 or later

* Apache Tomcat 9.0.98 or later

2. Disable Write Permissions for Default Servlet: If upgrading is not immediately feasible, disable write permissions for the default servlet by setting the readonly parameter to true in the web.xml file.

3. Restrict Partial PUT Support: Review and restrict partial PUT support to minimize the attack surface.

4. Implement Strict File Upload and Storage Policies: Enforce strict file upload and storage policies to prevent the uploading of malicious files or the manipulation of existing files.

5. Audit Application Configurations: Thoroughly audit your application configurations for any potential deserialization risks, especially if using file-based session persistence.

6. Apply Least Privilege Principles: Apply least privilege principles to web application configurations to minimize the impact of potential vulnerabilities.

7. Monitor Official Channels: If you cannot upgrade immediately, closely monitor official Apache Tomcat channels for any further security updates or patches related to this vulnerability. You can also refer to the oss-security mailing list for community discussions.

By implementing these measures, security professionals can significantly reduce the risk posed by CVE-2025-24813 and protect their Apache Tomcat deployments from potential exploitation. Proactive patching, following security best practices, and implementing defense-in-depth strategies are essential for maintaining the security and integrity of your web applications. For related vulnerabilities, see CVE-2024-3400 and other recent vulnerability fixes. If upgrading isn't possible right away, consider using a VPN as a temporary measure to add an extra layer of security. Also, enhancing your security posture with SOAR can automate threat detection and incident response. It's vital to maintain updated security logging and monitoring practices.

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