CVE-2022-37259 is a Regular Expression Denial of Service (ReDoS) vulnerability identified in the JavaScript library stealjs, specifically version 2.2.4, within the babel.js component. The flaw arises from the use of a vulnerable regular expression pattern that can be exploited by an attacker by supplying a crafted string input to the affected function. This crafted input triggers excessive backtracking in the regular expression engine, causing the process to consume an inordinate amount of CPU resources and leading to a denial of service condition. The vulnerability does not impact confidentiality or integrity but severely affects availability by potentially causing application or service unresponsiveness. The CVSS v3.1 base score is 7.5 (high severity), reflecting that the attack can be launched remotely over the network without any authentication or user interaction, and requires low attack complexity. The scope remains unchanged, meaning the vulnerability affects only the vulnerable component without extending to other system components. No known public exploits have been reported in the wild as of the publication date, and no official patches or fixes have been linked, which may indicate that remediation requires manual intervention or upgrading to a fixed version if available. The underlying weakness is classified under CWE-1333, which relates to inefficient regular expressions leading to performance degradation.

For European organizations, the impact of this ReDoS vulnerability can be significant, especially for those relying on stealjs 2.2.4 in their web applications or services. Exploitation could lead to service outages or degraded performance, affecting user experience and potentially causing financial losses due to downtime. Organizations in sectors such as e-commerce, finance, healthcare, and public services, which often have stringent availability requirements, could face operational disruptions. Additionally, denial of service conditions may be leveraged as part of multi-vector attacks or to distract security teams while other attacks are conducted. Since the vulnerability can be triggered remotely without authentication, it increases the attack surface and risk exposure. The absence of known exploits in the wild suggests limited active exploitation currently, but the high severity score and ease of exploitation warrant proactive mitigation to prevent future attacks.

To mitigate CVE-2022-37259, European organizations should first identify any usage of stealjs version 2.2.4 within their software stack, particularly focusing on components that utilize babel.js. If possible, upgrade to a patched or newer version of stealjs where the vulnerable regular expression has been fixed. If no official patch exists, consider applying custom fixes by reviewing and refactoring the vulnerable regular expression patterns to avoid catastrophic backtracking. Implement input validation and sanitization to restrict or reject suspiciously long or complex string inputs that could trigger the ReDoS condition. Employ runtime monitoring and resource usage alerts to detect abnormal CPU spikes indicative of ReDoS exploitation attempts. Additionally, deploying Web Application Firewalls (WAFs) with rules designed to detect and block malicious payloads targeting regular expression vulnerabilities can provide an additional layer of defense. Finally, incorporate this vulnerability into incident response and threat hunting activities to quickly identify and respond to any exploitation attempts.