Analysis Summary

A new security vulnerability, CVE-2025-46701, was disclosed on May 29, 2025, affecting Apache Tomcat’s CGI servlet implementation. This flaw arises from improper case sensitivity handling in the pathInfo component of URLs mapped to the CGI servlet. When Tomcat is deployed on case-insensitive file systems with security constraints applied to the pathInfo, attackers can craft URLs to bypass these security controls. Although the vulnerability is rated low severity, it poses a significant risk in scenarios where strict access controls rely on CGI-based configurations.

The vulnerability impacts a wide range of Tomcat versions, including Tomcat 11.0.0-M1 to 11.0.6, 10.1.0-M1 to 10.1.40, and 9.0.0-M1 to 9.0.104. While CGI support is disabled by default in all Tomcat versions, the issue affects systems where it has been explicitly enabled, particularly in legacy setups or development workflows. This makes the vulnerability less likely to affect default installations, but still critical for organizations that have enabled CGI functionality for specific use cases.

In response, the Apache Software Foundation (ASF) has released patched versions of Tomcat 11.0.7, 10.1.41, and 9.0.105, which correct the case sensitivity flaw in the CGI servlet. ASF has emphasized that standard Tomcat deployments without CGI enabled are not vulnerable. Nevertheless, system administrators are strongly advised to verify whether CGI support is active in their environments and to apply the patched updates immediately if applicable. If CGI functionality is not needed, it should be kept disabled to reduce the attack surface.

The vulnerability was responsibly disclosed by a security researcher, highlighting the importance of scrutinizing even less commonly used components of widely deployed software. Organizations are encouraged to maintain regular security audits, stay updated with vendor advisories, and reassess their configurations to ensure strict access control policies remain enforced. Although this is not a high-severity issue, its potential to undermine existing security constraints makes it a relevant concern for enterprise environments using Apache Tomcat with CGI enabled.

Impact

• Security Bypass
• Gain Access

Indicators of Compromise

CVE

• CVE-2025-46701

Affected Vendors

Remediation

• Refer to the Apache Website for patch, upgrade, or suggested workaround information.
• CGI is disabled by default in all Tomcat versions; ensure it remains disabled to eliminate exposure.
• Upgrade to the patched versions immediately if CGI is enabled: For Tomcat 11: upgrade to 11.0.7, for Tomcat 10: upgrade to 10.1.41, and for Tomcat 9: upgrade to 9.0.105.
• Identify whether the CGI servlet is enabled and if security constraints are applied to the pathInfo.
• Review security rules and ensure they are not dependent on case-insensitive assumptions, especially on case-insensitive file systems.
• Check that security constraints tied to CGI servlets and pathInfo are properly enforced in your web.xml or other configuration files.
• Implement routine vulnerability scans and manual audits for all Tomcat instances to catch misconfigurations early.
• Subscribe to the Apache Tomcat announce mailing list or monitor the ASF website for future vulnerabilities and patches.