CVE-2024-11831 identifies a cross-site scripting vulnerability in the npm package serialize-javascript, specifically version 6.0. The vulnerability stems from improper neutralization of input during web page generation, where the module fails to adequately sanitize certain JavaScript inputs such as regular expressions or complex object types. When these inputs are serialized and subsequently deserialized by a web browser, malicious code injected by an attacker can execute within the client context. This XSS flaw can lead to unauthorized script execution, enabling attackers to steal session tokens, manipulate web content, or perform actions on behalf of authenticated users. The vulnerability requires an attacker to have some level of privileges (PR:L) and user interaction (UI:R), and it affects the confidentiality and integrity of affected systems without impacting availability. The scope is considered changed (S:C) because the vulnerability can affect multiple components or users once exploited. Although no public exploits are currently known, the vulnerability is critical in environments where serialized data is transmitted to web clients, such as single-page applications or server-side rendered apps using serialize-javascript. The CVSS 3.1 vector is AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N, indicating network attack vector, low attack complexity, required privileges, user interaction, and partial impact on confidentiality and integrity. This vulnerability highlights the risks of improper input sanitization in serialization libraries widely used in JavaScript ecosystems.

For European organizations, the impact of CVE-2024-11831 can be significant, especially for those relying on serialize-javascript in their web application stacks. Successful exploitation could lead to cross-site scripting attacks that compromise user data confidentiality, including session cookies and personal information, potentially violating GDPR requirements. Integrity of web content could be undermined, allowing attackers to inject fraudulent content or redirect users to malicious sites. Although availability is not directly impacted, the reputational damage and potential regulatory penalties from data breaches could be severe. Organizations in sectors such as finance, healthcare, e-commerce, and government, which handle sensitive user data, are particularly at risk. The vulnerability could also facilitate lateral movement or further exploitation if combined with other vulnerabilities. Since the attack requires some privileges and user interaction, internal applications or portals with authenticated users are also vulnerable. The lack of known exploits provides a window for proactive mitigation, but the widespread use of npm packages in European software development means many organizations could be affected if they have not updated or audited their dependencies.

European organizations should immediately audit their software dependencies to identify usage of serialize-javascript version 6.0. If found, they should upgrade to a patched version once available or apply vendor-provided patches. In the absence of patches, implement strict input validation and sanitization on all data passed to serialization functions, especially for user-controllable inputs such as regex or complex objects. Employ Content Security Policy (CSP) headers to restrict script execution contexts and reduce the impact of potential XSS payloads. Conduct thorough code reviews focusing on serialization and deserialization logic to detect unsafe patterns. Use runtime application self-protection (RASP) or web application firewalls (WAF) configured to detect and block typical XSS attack vectors. Educate developers on secure coding practices around serialization and deserialization. Monitor application logs and user reports for signs of XSS exploitation attempts. Finally, integrate dependency scanning tools into CI/CD pipelines to catch vulnerable package versions early in the development lifecycle.