CVE-2024-11831 is a medium-severity vulnerability classified as Cross-site Scripting (XSS) found in the npm package serialize-javascript, specifically version 6.0. The vulnerability arises due to improper neutralization of input during web page generation. The serialize-javascript module is used to serialize JavaScript objects into strings that can be safely embedded in web pages or sent to clients. However, this particular flaw allows certain inputs, such as regular expressions or other JavaScript object types, to bypass sanitization. Consequently, an attacker can inject malicious JavaScript code that executes in the context of the victim's browser when the serialized data is deserialized and rendered. This can lead to theft of sensitive information, session hijacking, or other malicious actions typical of XSS attacks. The vulnerability requires that the attacker have some level of privileges (PR:L) and user interaction (UI:R) to exploit, but it can affect the confidentiality and integrity of data. The scope is changed (S:C), meaning the vulnerability can affect components beyond the initially vulnerable module. The CVSS score is 5.4, reflecting a medium severity level. No known exploits are currently reported in the wild, but the criticality of XSS in web applications means that exploitation could have significant consequences if leveraged in targeted attacks. This vulnerability is particularly relevant in environments where serialized JavaScript data is sent to web clients, such as server-side rendered applications or APIs that embed serialized data in responses. Without proper patching or mitigation, affected applications risk client-side code injection and subsequent compromise of user sessions or data.

For European organizations, the impact of CVE-2024-11831 can be significant, especially for those relying on Node.js ecosystems and npm packages like serialize-javascript in their web applications. The vulnerability can lead to client-side code execution, enabling attackers to steal cookies, tokens, or other sensitive data, potentially violating GDPR requirements on data protection and privacy. This can result in regulatory penalties, reputational damage, and loss of customer trust. E-commerce platforms, financial services, healthcare providers, and public sector websites are particularly at risk due to the sensitive nature of their data and the high value of their user sessions. Additionally, XSS vulnerabilities can be used as a foothold for further attacks, such as delivering malware or conducting phishing campaigns targeting European users. Given the widespread use of JavaScript serialization in modern web development, many organizations may be indirectly affected if they use third-party libraries or frameworks that depend on serialize-javascript. The medium severity rating suggests that while exploitation is not trivial, the potential for data leakage and session compromise remains a serious concern.

To mitigate CVE-2024-11831, European organizations should: 1) Immediately update the serialize-javascript package to a patched version once available, or apply vendor-provided patches. 2) Audit all dependencies and transitive dependencies in their Node.js projects to identify usage of serialize-javascript version 6.0 and replace or upgrade accordingly. 3) Implement Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in browsers, reducing the impact of potential XSS payloads. 4) Employ strict input validation and output encoding on all user-supplied data before serialization to minimize injection vectors. 5) Use security-focused code reviews and automated scanning tools to detect unsafe serialization or deserialization patterns. 6) Monitor web application logs and client-side error reports for signs of exploitation attempts. 7) Educate developers on secure coding practices related to serialization and deserialization of JavaScript objects. These steps go beyond generic advice by focusing on dependency management, layered defenses, and proactive detection tailored to this specific vulnerability.