CVE-2024-12397 is a high-severity vulnerability affecting Quarkus-HTTP, a component used in the Quarkus framework for handling HTTP requests. The flaw arises from incorrect parsing of cookies containing certain value-delimiting characters in incoming HTTP requests. This parsing inconsistency can be exploited by an attacker to craft malicious cookie values that bypass normal security controls. Specifically, the attacker can leverage this flaw to exfiltrate HttpOnly cookies, which are designed to be inaccessible to client-side scripts, or to spoof additional arbitrary cookie values. Such manipulation can lead to unauthorized access to sensitive data or modification of data integrity within the affected application. The vulnerability is categorized under HTTP Request/Response Smuggling, a class of attacks that exploit discrepancies in how different systems parse HTTP requests, enabling attackers to interfere with the intended request processing. The CVSS v3.1 base score is 7.4, indicating a high severity level, with the vector showing that the attack can be performed remotely without privileges or user interaction but requires high attack complexity. The primary impact is on confidentiality and integrity, with no direct impact on availability. No known exploits are currently reported in the wild, and no patches or vendor advisories have been linked yet. This vulnerability requires careful attention due to the sensitive nature of cookie data and the widespread use of Quarkus in modern Java applications and microservices architectures.

For European organizations, this vulnerability poses a significant risk to the confidentiality and integrity of user session data and other sensitive information managed via cookies. Many enterprises in Europe rely on Quarkus for cloud-native applications, microservices, and APIs, especially in sectors like finance, healthcare, and government services where data protection is paramount. Exploitation could lead to unauthorized data access, session hijacking, or privilege escalation, potentially violating GDPR requirements and resulting in legal and reputational damage. The flaw could also undermine trust in web applications by allowing attackers to manipulate session cookies or steal authentication tokens. Since the vulnerability does not require user interaction or authentication, it could be exploited remotely, increasing the attack surface. Although no active exploitation is reported yet, the potential for targeted attacks against critical infrastructure or high-value targets in Europe is considerable, especially given the strategic importance of data confidentiality in the region.

European organizations should prioritize the following specific mitigation steps: 1) Monitor official Quarkus security advisories and apply patches immediately once available, as no patch links are currently provided. 2) Implement strict input validation and sanitization on HTTP headers and cookies at the application and web server layers to detect and block suspicious delimiters or malformed cookie values. 3) Employ Web Application Firewalls (WAFs) with custom rules to detect and mitigate HTTP request smuggling patterns, focusing on cookie parsing anomalies. 4) Use secure cookie attributes such as HttpOnly, Secure, and SameSite to reduce the risk of cookie theft and cross-site request forgery. 5) Conduct thorough security testing, including fuzzing and penetration testing, targeting cookie parsing logic to identify and remediate similar parsing inconsistencies. 6) Review and harden reverse proxy and load balancer configurations to ensure consistent HTTP request parsing across all components. 7) Educate development teams about secure cookie handling and the risks of HTTP request smuggling to prevent introduction of similar vulnerabilities in future code. These steps go beyond generic advice by focusing on cookie-specific defenses and infrastructure-level consistency checks.