CVE-2023-46750 is classified as a CWE-601 Open Redirect vulnerability found in the Apache Shiro framework, specifically when form-based authentication is enabled. Apache Shiro is a widely used Java security framework that provides authentication, authorization, cryptography, and session management. The vulnerability arises because the framework improperly validates redirect URLs after authentication, allowing an attacker to manipulate the redirect parameter to point to an untrusted external site. This can be exploited by crafting malicious URLs that, when clicked by a user, redirect them to phishing or malicious websites. The vulnerability affects all versions of Apache Shiro prior to 1.13.0 and 2.0.0-alpha-4, including early alpha releases. The CVSS 3.1 base score is 4.7, reflecting a medium severity level due to the network attack vector, low attack complexity, no privileges required, but requiring user interaction. The impact is primarily on confidentiality, as users may be tricked into divulging credentials or sensitive data on attacker-controlled sites. Integrity and availability are not directly affected. No known exploits have been reported in the wild as of the publication date (December 14, 2023). The recommended mitigation is to upgrade Apache Shiro to version 1.13.0 or later, or 2.0.0-alpha-4 or later, where the redirect validation logic has been corrected to prevent open redirects.

For European organizations, this vulnerability poses a moderate risk primarily through social engineering and phishing attacks facilitated by open redirects. Attackers can exploit this flaw to redirect authenticated users to malicious sites that mimic legitimate services, potentially harvesting credentials or delivering malware. This can undermine user trust and lead to data breaches or account compromise. Organizations with customer-facing web applications or internal portals using vulnerable Apache Shiro versions are at risk. The vulnerability does not directly compromise system integrity or availability but can be a stepping stone for more sophisticated attacks. The impact is heightened in sectors with sensitive data such as finance, healthcare, and government services. Additionally, regulatory frameworks like GDPR impose strict requirements on data protection, so exploitation leading to data leakage could result in legal and financial penalties.

The primary mitigation is to upgrade Apache Shiro to version 1.13.0 or later, or 2.0.0-alpha-4 or later, where the open redirect vulnerability has been fixed. Organizations should audit their applications to identify usage of vulnerable Shiro versions, especially those employing form-based authentication. Implement strict validation and sanitization of redirect URLs on the server side to ensure they only point to trusted internal domains. Employ Content Security Policy (CSP) headers to reduce the risk of redirection-based attacks. Educate users and administrators about phishing risks associated with open redirects. Monitor web traffic for suspicious redirect patterns and consider deploying web application firewalls (WAFs) with rules targeting open redirect attempts. Finally, integrate this vulnerability into vulnerability management and patching cycles to ensure timely updates.