CVE-2022-42960 is a medium-severity vulnerability affecting multiple versions of the EqualWeb Accessibility Widget, specifically versions 2.0.0 through 4.0.1. The vulnerability arises from improper validation of message events handled by the accessibility.js script, which leads to a DOM-based Cross-Site Scripting (XSS) flaw (CWE-79). This type of XSS occurs when untrusted data is injected into the Document Object Model (DOM) without proper sanitization or encoding, allowing an attacker to execute arbitrary JavaScript code in the context of the victim's browser. The vulnerability is exploitable remotely over the network (Attack Vector: Network) without requiring any privileges (PR:N) but does require user interaction (UI:R), such as visiting a maliciously crafted webpage or clicking a link. The impact primarily affects confidentiality and integrity, as attackers can steal sensitive information like cookies, session tokens, or perform actions on behalf of the user, but it does not affect availability. The CVSS v3.1 base score is 5.4, reflecting a medium severity level. No known exploits are currently reported in the wild, and no official patches or vendor advisories are linked in the provided data. The vulnerability affects web applications that integrate the EqualWeb Accessibility Widget, which is designed to improve website accessibility compliance. Since this widget is client-side JavaScript code embedded in websites, any website using vulnerable versions is at risk of DOM XSS attacks if an attacker can deliver malicious messages to the widget's message event handler. This could be leveraged in phishing campaigns or by injecting malicious content into third-party resources that interact with the widget. Given the widget's role in accessibility, it is often deployed on websites aiming to comply with accessibility regulations, including public sector and private organizations in Europe.

For European organizations, the impact of CVE-2022-42960 can be significant, especially for those required to meet stringent accessibility and data protection regulations such as the EU Web Accessibility Directive and GDPR. Exploitation of this DOM XSS vulnerability could lead to unauthorized disclosure of personal data, session hijacking, or manipulation of user interactions, undermining user trust and potentially resulting in regulatory penalties. Public sector websites, educational institutions, and large enterprises that rely on the EqualWeb Accessibility Widget to meet accessibility standards are particularly at risk. The vulnerability could be exploited to target users with disabilities who rely on accessibility tools, potentially causing harm or misinformation. Although the vulnerability does not directly impact system availability, the reputational damage and compliance risks are considerable. Additionally, attackers could use this vulnerability as a foothold to conduct further attacks such as phishing or delivering malware payloads through compromised websites. Since no known exploits are reported, the threat is currently theoretical but should be addressed proactively to prevent future exploitation.

1. Immediate mitigation involves updating or replacing the EqualWeb Accessibility Widget with a version that properly validates and sanitizes message events. Since no official patches are listed, organizations should contact EqualWeb or their service provider for updated versions or security advisories. 2. Implement Content Security Policy (CSP) headers with strict script-src and object-src directives to limit the execution of unauthorized scripts and reduce the impact of DOM XSS. 3. Conduct a thorough audit of all web applications using the EqualWeb widget to identify affected versions and remove or disable vulnerable instances if updates are unavailable. 4. Employ runtime application self-protection (RASP) or web application firewalls (WAF) with custom rules to detect and block suspicious message event payloads targeting accessibility.js. 5. Educate web developers and administrators about secure handling of postMessage events and the risks of DOM XSS, ensuring secure coding practices in future widget integrations. 6. Monitor web traffic and logs for unusual activity related to message events or script injections. 7. For organizations with high compliance requirements, consider alternative accessibility solutions with verified security postures until this vulnerability is resolved.