CVE-2022-37265 is a critical prototype pollution vulnerability identified in the JavaScript library stealjs version 2.2.4, specifically via the alias variable in babel.js. Prototype pollution occurs when an attacker is able to manipulate the prototype of a base object, such as Object.prototype, by injecting or modifying properties. This can lead to unexpected behavior in applications, including the ability to escalate privileges, execute arbitrary code, or cause denial of service. In this case, the vulnerability allows an unauthenticated remote attacker to exploit the alias variable without any user interaction, leading to full compromise of confidentiality, integrity, and availability of affected systems. The CVSS 3.1 score of 9.8 reflects the severity, with network attack vector, low attack complexity, no privileges required, and no user interaction needed. The vulnerability is categorized under CWE-1321, which relates to improper handling of prototype pollution in JavaScript. Although no specific vendor or product is listed, stealjs is a JavaScript module loader used in web applications and development environments, and babel.js is a widely used JavaScript compiler toolchain component. The lack of patch links suggests that at the time of publication, no official fix was available. No known exploits in the wild have been reported yet, but the critical severity and ease of exploitation make it a significant threat to any applications using the vulnerable version of stealjs.

For European organizations, the impact of this vulnerability can be substantial, especially for those relying on stealjs in their web development pipelines or production environments. Exploitation could allow attackers to manipulate application behavior, inject malicious code, or disrupt services, potentially leading to data breaches, loss of service availability, and damage to organizational reputation. Given the critical nature of the vulnerability, attackers could leverage it to gain persistent footholds or move laterally within networks. Industries with high reliance on web applications, such as finance, healthcare, and government services, are particularly at risk. Additionally, the vulnerability could affect supply chains if third-party software or libraries incorporate the vulnerable stealjs version, amplifying the risk across multiple organizations. The absence of known exploits in the wild currently reduces immediate risk but does not diminish the urgency for mitigation, as attackers may develop exploits rapidly given the public disclosure.

To mitigate this vulnerability, European organizations should first identify any usage of stealjs version 2.2.4 in their environments, including direct dependencies and transitive dependencies in web applications and development tools. Immediate steps include upgrading to a patched version of stealjs once available or applying community or vendor-provided patches if official fixes are delayed. In the interim, organizations should implement strict input validation and sanitization to prevent malicious payloads from reaching vulnerable code paths. Employing Content Security Policy (CSP) headers can help limit the impact of injected scripts. Additionally, monitoring application behavior for anomalies and deploying runtime application self-protection (RASP) tools can detect and block exploitation attempts. Regular dependency scanning and software composition analysis (SCA) should be enhanced to detect vulnerable versions proactively. Finally, organizations should engage with their software supply chain partners to ensure that patched versions are adopted promptly to prevent indirect exposure.