CVE-2025-46701 is a high-severity vulnerability affecting multiple versions of the Apache Tomcat server, specifically related to the handling of case sensitivity in the CGI servlet's pathInfo component of a URI. The vulnerability stems from improper handling of case sensitivity (CWE-178) within the GCI servlet, which allows an attacker to bypass security constraints that are intended to restrict access to certain URI paths. This flaw affects Apache Tomcat versions from 8.5.0 through 8.5.100 (EOL but known 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 issue is resolved in versions 8.5.101+, 9.0.105+, 10.1.41+, and 11.0.7+. The vulnerability allows an unauthenticated remote attacker to bypass security constraints without user interaction, potentially leading to unauthorized access to restricted resources. The CVSS v3.1 base score is 7.3, indicating a high severity with network attack vector, low attack complexity, no privileges required, and no user interaction needed. The impact includes potential confidentiality, integrity, and availability compromises due to unauthorized access and possible exploitation of protected application functionality. No known exploits are currently reported in the wild, but the vulnerability's nature and ease of exploitation make it a significant risk for affected deployments.

For European organizations, the impact of CVE-2025-46701 can be substantial, especially for those relying on Apache Tomcat for web application hosting, including government agencies, financial institutions, healthcare providers, and critical infrastructure operators. Unauthorized bypass of security constraints could lead to exposure of sensitive data, unauthorized execution of application functions, or disruption of services. Given Apache Tomcat's widespread use in enterprise environments across Europe, exploitation could result in data breaches, compliance violations (e.g., GDPR), and operational disruptions. The vulnerability's ability to be exploited remotely without authentication increases the risk of automated attacks and large-scale scanning campaigns targeting vulnerable servers. Organizations with legacy or EOL versions of Tomcat are particularly at risk if they have not applied patches or mitigations. The potential for lateral movement within networks and pivoting to other systems also raises the threat level for European enterprises.

1. Immediate upgrade to fixed Apache Tomcat versions: 11.0.7, 10.1.41, or 9.0.105 (or later) to ensure the vulnerability is patched. 2. For environments where immediate upgrade is not feasible, implement strict network-level access controls to restrict access to Tomcat servers, limiting exposure to trusted IP addresses only. 3. Employ Web Application Firewalls (WAFs) with custom rules to detect and block suspicious URI patterns that attempt to exploit case sensitivity bypasses. 4. Conduct thorough audits of existing security constraints and URI mappings in Tomcat configurations to identify and remediate any potential misconfigurations that could be exploited. 5. Monitor logs for unusual access patterns or attempts to bypass security constraints, focusing on case variations in URI paths. 6. Apply defense-in-depth by isolating critical Tomcat instances and limiting privileges of the Tomcat process to reduce impact in case of compromise. 7. Educate development and operations teams about the importance of case sensitivity in URI handling and security constraint enforcement to prevent similar issues in custom applications.