CVE-2024-27982 is a vulnerability identified in the HTTP server component of NodeJS, affecting all major versions from 4.0 through 21.0. The flaw arises from improper parsing of HTTP headers when a malformed header includes a space character before the 'Content-Length' header. This causes the NodeJS HTTP server to misinterpret the header, enabling an attacker to perform HTTP request smuggling. HTTP request smuggling is a technique where an attacker crafts a single HTTP request that is interpreted differently by front-end and back-end servers, allowing the attacker to 'smuggle' a second HTTP request within the body of the first. This can lead to various downstream attacks such as cache poisoning, cross-site scripting, session hijacking, and bypassing security controls. The vulnerability is classified under CWE-444 (Inconsistent Interpretation of HTTP Requests), highlighting the root cause as inconsistent parsing of HTTP headers. The CVSS 3.0 score is 6.5 (medium severity), with the vector indicating network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), no confidentiality impact (C:N), low integrity impact (I:L), and low availability impact (A:L). No known exploits are currently reported in the wild, and no official patches have been linked yet. However, given the widespread use of NodeJS in web servers and applications, this vulnerability poses a significant risk if exploited. The vulnerability allows attackers to inject unauthorized HTTP requests, potentially leading to manipulation of web traffic and unauthorized actions on affected systems.

For European organizations, the impact of this vulnerability can be substantial due to the extensive adoption of NodeJS in web applications, microservices, and backend APIs across industries such as finance, e-commerce, healthcare, and government services. HTTP request smuggling can enable attackers to bypass security controls, poison caches, hijack user sessions, and perform unauthorized actions, which could lead to data integrity issues and partial service disruptions. Although confidentiality is not directly impacted, the integrity and availability of services can be compromised, potentially affecting business operations and customer trust. Organizations relying on NodeJS-based infrastructure may face increased risk of targeted attacks exploiting this vulnerability, especially in environments where multiple proxies or load balancers are used, as these setups are more susceptible to request smuggling. The absence of required authentication or user interaction increases the attack surface, making automated exploitation feasible. Given the medium CVSS score but the critical nature of HTTP request smuggling attacks in complex web environments, European enterprises should prioritize assessment and mitigation to prevent potential exploitation.

1. Immediate mitigation involves reviewing and updating NodeJS versions to the latest patched release once available. Until patches are released, organizations should implement strict input validation and HTTP header sanitization at the application and proxy layers to detect and block malformed headers with leading spaces before 'Content-Length'. 2. Deploy Web Application Firewalls (WAFs) with updated rules to detect HTTP request smuggling patterns, specifically targeting malformed headers and suspicious request bodies. 3. Configure reverse proxies and load balancers to normalize HTTP headers and reject requests with ambiguous or malformed headers. 4. Conduct thorough security testing, including fuzzing and penetration testing focused on HTTP request smuggling scenarios, to identify vulnerable endpoints. 5. Monitor network traffic for anomalies indicative of request smuggling attacks, such as unexpected request sequences or duplicated requests. 6. Educate development and operations teams about the risks of HTTP request smuggling and encourage secure coding practices around HTTP header parsing. 7. Where feasible, segment critical services and apply strict access controls to limit the impact of potential exploitation. 8. Maintain up-to-date inventories of NodeJS versions in use across the organization to prioritize patching and risk assessment efforts.