CVE-2022-31147 is a vulnerability in the jQuery Validation Plugin (jquery-validation), a widely used JavaScript library that provides client-side form validation. The affected versions are all releases prior to 1.19.5. The vulnerability arises from inefficient regular expression complexity in the url2 method, which can be triggered when an attacker supplies crafted input to this function. This leads to a Regular Expression Denial of Service (ReDoS) attack, where the processing of maliciously crafted input causes excessive CPU consumption and delays, effectively degrading or denying service. This issue is a consequence of an incomplete fix for a previous vulnerability (CVE-2021-43306). The vulnerability is categorized under CWE-1333, which relates to inefficient regular expression complexity causing performance issues. Exploitation does not require authentication but does require the attacker to supply input that reaches the vulnerable url2 method, typically through form fields validated by jquery-validation. There are no known exploits in the wild as of the published date. The recommended remediation is to upgrade to jquery-validation version 1.19.5 or later, where the issue has been patched. Since jquery-validation is a client-side library, the impact depends on the context in which it is used, but it can affect web applications relying on this plugin for input validation, potentially leading to degraded user experience or denial of service for legitimate users due to resource exhaustion on the client or server side if server-side validation relies on similar logic.

For European organizations, the impact of CVE-2022-31147 primarily concerns web applications that utilize vulnerable versions of jquery-validation for client-side form validation. The ReDoS vulnerability can be exploited by attackers to cause excessive CPU usage, leading to slowdowns or outages of web services. This can degrade user experience, reduce availability of critical web applications, and potentially disrupt business operations. Organizations in sectors with high reliance on web portals—such as e-commerce, finance, public services, and healthcare—may face increased risk of service disruption. While the vulnerability is client-side, if the server relies on client-side validation or processes similar regex patterns, server resources could also be impacted, amplifying the denial of service effect. Additionally, attackers could use this vulnerability as part of a broader attack chain to distract or degrade defenses. However, since no known exploits are reported in the wild, the immediate threat level is moderate but should not be underestimated given the widespread use of jquery-validation in web applications across Europe.

1. Immediate upgrade of all jquery-validation instances to version 1.19.5 or later to apply the official patch. 2. Conduct an inventory of all web applications and services to identify usage of jquery-validation, especially versions prior to 1.19.5. 3. Implement server-side input validation as a complementary control to client-side validation to reduce reliance on potentially vulnerable client-side logic. 4. Monitor web application performance and logs for unusual CPU spikes or slowdowns that could indicate attempted ReDoS attacks. 5. Employ Web Application Firewalls (WAFs) with custom rules to detect and block suspicious input patterns targeting the url2 method or similar regex-based validation routines. 6. Educate development teams about the risks of inefficient regular expressions and encourage secure coding practices, including the use of regex timeouts or complexity limits. 7. For critical applications, consider rate limiting or CAPTCHA challenges on form submissions to reduce the risk of automated abuse exploiting this vulnerability.