CVE-2025-46701 is a vulnerability classified under CWE-178, relating to improper handling of case sensitivity in Apache Tomcat's CGI servlet. The issue arises because the servlet incorrectly processes the case of the pathInfo component in URIs, which can be exploited to bypass security constraints that are intended to restrict access to certain resources. Specifically, security constraints applied to the pathInfo are circumvented when attackers manipulate the case of characters in the URI, effectively allowing unauthorized access to protected resources. This vulnerability affects multiple Apache Tomcat versions, including 8.5.0 through 8.5.100 (EOL but affected), 9.0.0.M1 through 9.0.104, 10.1.0-M1 through 10.1.40, and 11.0.0-M1 through 11.0.6. The flaw does not require any privileges or user interaction to exploit, making it remotely exploitable over the network. The CVSS v3.1 base score is 7.3, indicating high severity, with impacts on confidentiality, integrity, and availability. The vulnerability was publicly disclosed on May 29, 2025, with no known exploits in the wild at the time of disclosure. The Apache Software Foundation has released fixed versions 11.0.7, 10.1.41, and 9.0.105 to address this issue. Organizations using affected versions should upgrade promptly to mitigate risk. The vulnerability is particularly critical for environments where Tomcat is used to serve sensitive web applications or APIs, as unauthorized access could lead to data leakage, unauthorized actions, or service disruption.

For European organizations, the impact of CVE-2025-46701 can be significant due to the widespread use of Apache Tomcat in enterprise web applications, government portals, and critical infrastructure services. Exploitation could lead to unauthorized access to sensitive data, bypass of authentication and authorization controls, and potential disruption of services. This could result in data breaches, regulatory non-compliance (e.g., GDPR violations), reputational damage, and operational downtime. Sectors such as finance, healthcare, public administration, and telecommunications are particularly at risk given their reliance on web applications hosted on Tomcat servers. The vulnerability’s ability to bypass security constraints without authentication increases the risk profile, making it easier for attackers to gain footholds in networks. Additionally, the flaw affects multiple major Tomcat branches, increasing the attack surface across diverse deployments. The absence of known exploits currently provides a window for proactive mitigation, but the high severity score and ease of exploitation necessitate urgent action.

1. Immediately upgrade Apache Tomcat to the fixed versions: 11.0.7, 10.1.41, or 9.0.105 depending on your deployment. 2. Audit all web applications using the CGI servlet to identify usage of pathInfo components and verify that security constraints are correctly enforced post-upgrade. 3. Implement strict access controls and input validation on URIs, particularly focusing on case sensitivity handling in web server and application configurations. 4. Employ Web Application Firewalls (WAFs) with rules designed to detect and block suspicious URI manipulations that exploit case sensitivity issues. 5. Monitor logs for unusual access patterns or attempts to bypass security constraints via case variations in URLs. 6. For legacy systems that cannot be immediately upgraded, consider disabling the CGI servlet if not required or restricting its usage to trusted networks. 7. Conduct penetration testing focused on URI manipulation to ensure that security constraints cannot be bypassed. 8. Maintain an incident response plan to quickly address any exploitation attempts. 9. Stay informed about any emerging exploits or patches related to this vulnerability.