CVE-2024-12397 is a vulnerability identified in the Quarkus-HTTP component, which improperly parses HTTP cookies containing certain value-delimiting characters. This parsing inconsistency can be exploited by attackers to craft malicious cookie values that bypass normal security controls. Specifically, the flaw allows attackers to exfiltrate HttpOnly cookies—cookies that are normally inaccessible to client-side scripts—thereby compromising the confidentiality of session tokens or other sensitive data stored in cookies. Additionally, attackers can inject arbitrary cookie values, potentially leading to unauthorized data modification or session manipulation. The root cause lies in inconsistent interpretation of cookie delimiters during HTTP request parsing, a form of HTTP request/response smuggling. The vulnerability has a CVSS 3.1 base score of 7.4, indicating high severity, with network attack vector, high attack complexity, no privileges or user interaction required, and impacts on confidentiality and integrity but not availability. Although no active exploits have been reported, the flaw poses a significant risk to applications relying on Quarkus-HTTP for HTTP request handling, particularly those exposing sensitive user data or authentication tokens. The vulnerability underscores the criticality of robust HTTP parsing and cookie handling to prevent smuggling and related attacks that can lead to session hijacking or data leakage.

For European organizations, the impact of CVE-2024-12397 can be substantial, especially for those deploying Quarkus-based applications in sectors such as finance, healthcare, government, and e-commerce where sensitive personal or financial data is processed. Successful exploitation could lead to unauthorized access to HttpOnly cookies, which often contain session identifiers or authentication tokens, enabling attackers to hijack user sessions or escalate privileges. This compromises data confidentiality and integrity, potentially resulting in data breaches, regulatory non-compliance (e.g., GDPR violations), reputational damage, and financial losses. Since the vulnerability does not affect availability, denial-of-service is less of a concern, but the stealthy nature of cookie exfiltration increases the risk of prolonged undetected compromise. European organizations using cloud-native Java frameworks or microservices architectures that incorporate Quarkus-HTTP are particularly vulnerable. The lack of known exploits in the wild provides a window for proactive mitigation, but the high severity and ease of network-based exploitation necessitate urgent attention.

To mitigate CVE-2024-12397, European organizations should: 1) Immediately update Quarkus-HTTP to the latest patched version once available from the vendor or community to ensure the parsing flaw is corrected. 2) Implement strict input validation and sanitization on all incoming HTTP headers and cookies to reject or properly handle suspicious delimiter characters. 3) Employ Web Application Firewalls (WAFs) with rules designed to detect and block malformed or suspicious cookie headers indicative of request smuggling attempts. 4) Monitor HTTP traffic logs for unusual cookie patterns or anomalies that could signal exploitation attempts. 5) Conduct security testing, including fuzzing and penetration testing focused on HTTP request parsing and cookie handling, to identify residual weaknesses. 6) Educate developers and security teams about the risks of HTTP request smuggling and secure coding practices related to HTTP header parsing. 7) Where feasible, implement additional security controls such as HttpOnly and Secure flags on cookies, Content Security Policy (CSP), and same-site cookie attributes to limit cookie exposure. These targeted measures go beyond generic patching and help reduce the attack surface and detect exploitation attempts early.