CVE-2022-40664 is a critical authentication bypass vulnerability affecting Apache Shiro versions prior to 1.10.0. Apache Shiro is a widely used Java security framework that provides authentication, authorization, cryptography, and session management capabilities for enterprise applications. The vulnerability arises specifically when Shiro is used in conjunction with Java Servlet RequestDispatcher's forward or include methods. In such scenarios, improper handling of authentication checks allows an attacker to bypass authentication controls entirely. This means that an unauthenticated attacker can gain unauthorized access to protected resources or functionalities without providing valid credentials. The vulnerability is classified under CWE-287 (Improper Authentication), indicating a failure to correctly verify user identity before granting access. The CVSS v3.1 base score is 9.8 (critical), reflecting the high impact on confidentiality, integrity, and availability, combined with ease of exploitation (network vector, no privileges or user interaction required). Although no known exploits have been reported in the wild, the severity and nature of the flaw make it a significant risk for any application relying on vulnerable versions of Apache Shiro for security enforcement. The lack of available patches at the time of reporting underscores the urgency for organizations to upgrade to Shiro 1.10.0 or later, where this issue has been addressed.

For European organizations, the impact of CVE-2022-40664 can be severe. Many enterprises and public sector entities in Europe use Java-based web applications secured by Apache Shiro due to its modular and flexible security features. An authentication bypass can lead to unauthorized data access, modification, or deletion, potentially exposing sensitive personal data protected under GDPR. This could result in regulatory penalties, reputational damage, and operational disruptions. Additionally, attackers exploiting this vulnerability could escalate privileges within affected applications, leading to further lateral movement and compromise of internal systems. Critical infrastructure sectors such as finance, healthcare, and government services that rely on Shiro for access control are particularly at risk. The vulnerability’s network accessibility and lack of required authentication mean attackers can exploit it remotely without user interaction, increasing the likelihood of automated attacks and rapid exploitation across vulnerable deployments in Europe.

To mitigate CVE-2022-40664, European organizations should immediately assess their use of Apache Shiro and identify all applications running versions prior to 1.10.0. The primary mitigation is to upgrade Apache Shiro to version 1.10.0 or later, where the authentication bypass flaw has been fixed. If immediate upgrade is not feasible, organizations should implement compensating controls such as: 1) Restricting access to vulnerable applications by network segmentation and firewall rules to limit exposure to trusted users only. 2) Deploying Web Application Firewalls (WAFs) with custom rules to detect and block suspicious RequestDispatcher forward/include patterns that could trigger the bypass. 3) Enhancing application-level logging and monitoring to detect anomalous access patterns indicative of exploitation attempts. 4) Conducting thorough code reviews and penetration testing focused on authentication flows involving RequestDispatcher usage. 5) Applying strict input validation and ensuring that authentication checks are enforced consistently regardless of request dispatching. These targeted mitigations, combined with prompt patching, will reduce the attack surface and protect sensitive assets from unauthorized access.