CVE-2024-12225 is a critical authentication bypass vulnerability identified in the Quarkus framework, specifically within the quarkus-security-webauthn module. Quarkus is a popular Java framework designed for building cloud-native applications. The WebAuthn module facilitates user registration and login via REST endpoints, supporting both default and developer-customized endpoints. The vulnerability arises when developers implement custom REST endpoints for authentication but fail to disable or restrict access to the default endpoints. These default endpoints remain accessible and can be exploited by attackers to obtain a login cookie that does not correspond to any legitimate user or, depending on the application logic, may correspond to an existing user unrelated to the attacker. This flaw allows an attacker to impersonate any user simply by knowing the target user's username, bypassing authentication controls without requiring any credentials or user interaction. The CVSS 3.1 base score of 9.1 reflects the critical nature of this vulnerability, highlighting its network attack vector, low complexity, no privileges required, no user interaction, and high impact on confidentiality and integrity. The vulnerability does not affect availability. No known exploits are currently reported in the wild, but the potential for abuse is significant given the ease of exploitation and the sensitive nature of authentication mechanisms involved.

For European organizations, this vulnerability poses a severe risk to the confidentiality and integrity of user accounts and sensitive data. Organizations using Quarkus with the WebAuthn module in their authentication workflows could face unauthorized access incidents, leading to data breaches, identity theft, and potential lateral movement within internal networks. The ability to impersonate users without credentials undermines trust in authentication systems and can facilitate further attacks such as privilege escalation, data exfiltration, or fraud. Sectors such as finance, healthcare, government, and critical infrastructure in Europe, which often rely on robust authentication mechanisms, could be particularly impacted. Additionally, regulatory compliance frameworks like GDPR impose strict requirements on protecting personal data, and exploitation of this vulnerability could lead to significant legal and financial penalties. The lack of user interaction and low attack complexity means attackers can automate exploitation at scale, increasing the threat surface for European enterprises.

To mitigate this vulnerability, European organizations should immediately audit their Quarkus applications using the WebAuthn module to identify if custom REST endpoints have been implemented alongside accessible default endpoints. Developers must ensure that default authentication endpoints are disabled or properly secured when custom endpoints are in use. This can be achieved by configuring endpoint access controls, applying strict authentication and authorization checks, or removing default endpoints entirely from the deployed application. Additionally, organizations should update to the latest patched version of Quarkus once available, as vendors typically release fixes addressing such critical vulnerabilities. Implementing comprehensive logging and monitoring of authentication endpoints can help detect anomalous access patterns indicative of exploitation attempts. Employing Web Application Firewalls (WAFs) with rules targeting suspicious authentication requests may provide an additional layer of defense. Finally, organizations should conduct thorough security testing, including penetration testing focused on authentication flows, to validate the effectiveness of mitigations.