CVE-2022-37620 is a high-severity Regular Expression Denial of Service (ReDoS) vulnerability identified in the kangax html-minifier version 4.0.0. The vulnerability arises from the 'reCustomIgnore' regular expression used within the html-minifier tool. ReDoS vulnerabilities occur when an attacker crafts input that causes a regular expression engine to consume excessive CPU resources, leading to service degradation or denial of service. In this case, the flaw allows an unauthenticated remote attacker to trigger the vulnerability by submitting specially crafted input that exploits the inefficient regular expression pattern. The vulnerability does not impact confidentiality or integrity but severely affects availability by causing the html-minifier process to hang or consume excessive resources, potentially leading to denial of service. The CVSS 3.1 base score is 7.5 (high), reflecting the network attack vector, low attack complexity, no privileges or user interaction required, and a scope limited to the vulnerable component. No known exploits have been reported in the wild, and no patches or fixes are currently linked, indicating that users of this specific version should be cautious and consider mitigation strategies.

For European organizations, the impact of this vulnerability primarily concerns services or applications that incorporate the kangax html-minifier 4.0.0, especially those that process untrusted or user-supplied HTML content. Since html-minifier is often used in web development pipelines to optimize HTML files, its presence in build or runtime environments could be exploited to cause denial of service conditions, leading to service outages or degraded performance. This can affect web hosting providers, SaaS companies, and enterprises relying on automated HTML optimization. The denial of service could disrupt business operations, degrade user experience, and potentially cause cascading failures in dependent systems. Given the network attack vector and lack of required privileges, attackers could exploit this vulnerability remotely without authentication, increasing the risk surface. However, the absence of known exploits in the wild suggests the threat is currently theoretical but should be proactively addressed to prevent future exploitation.

European organizations should first identify whether kangax html-minifier 4.0.0 is used within their software development or production environments. If identified, immediate mitigation steps include: 1) Temporarily disabling or restricting access to services that utilize the vulnerable html-minifier until a patch or update is available. 2) Implement input validation and sanitization to limit the complexity and size of HTML content processed by the minifier, reducing the risk of triggering the ReDoS condition. 3) Employ resource limiting techniques such as CPU timeouts or process isolation (e.g., containerization) to prevent a single process from exhausting system resources. 4) Monitor system performance and logs for signs of unusual CPU spikes or service slowdowns indicative of exploitation attempts. 5) Engage with the maintainers of html-minifier or community forums to track the release of patches or safer versions and plan timely upgrades. 6) Consider alternative HTML minification tools with no known ReDoS vulnerabilities as a temporary workaround. These targeted measures go beyond generic advice by focusing on detection, containment, and proactive resource management specific to this vulnerability.