CVE-2026-22704 is a stored Cross-Site Scripting (XSS) vulnerability classified under CWE-79 that affects the HAX CMS platform, specifically its 'issues' product module. The vulnerability exists in versions 11.0.6 through 24.x.x, prior to the patched release 25.0.0. HAX CMS is used to manage microsite universes with PHP or Node.js backends, and the flaw stems from improper neutralization of user-supplied input during web page generation. This improper sanitization allows attackers to inject malicious JavaScript payloads that are stored persistently and executed in the browsers of users who access the affected pages. The CVSS v3.1 score of 8.1 reflects a high severity due to the vulnerability’s potential to compromise confidentiality, integrity, and availability. The attack vector is network-based (AV:N), requiring low privileges (PR:L) and user interaction (UI:R), with high complexity (AC:H). The scope is changed (S:C), indicating that exploitation can affect resources beyond the vulnerable component. Successful exploitation can lead to account takeover by stealing session tokens or performing actions on behalf of the victim user. Although no known exploits have been reported in the wild, the vulnerability poses a significant risk to organizations using vulnerable versions of HAX CMS. The issue was publicly disclosed in January 2026 and has been addressed in version 25.0.0, which includes proper input validation and output encoding to neutralize malicious scripts.

For European organizations, the impact of this vulnerability can be substantial, particularly for those relying on HAX CMS to manage microsites that may contain sensitive or business-critical information. Stored XSS can lead to account takeover, enabling attackers to impersonate legitimate users, escalate privileges, and access confidential data. This can result in data breaches, reputational damage, and regulatory non-compliance, especially under GDPR requirements. Additionally, attackers could use the vulnerability to distribute malware or conduct phishing campaigns targeting employees or customers. The disruption of microsite functionality could also affect marketing, communications, and customer engagement efforts. Organizations in sectors such as finance, healthcare, government, and critical infrastructure that use HAX CMS are at higher risk due to the sensitivity of their data and the potential for cascading effects on other systems.

To mitigate this vulnerability, European organizations should immediately upgrade all instances of HAX CMS to version 25.0.0 or later, where the vulnerability has been patched. In parallel, implement strict input validation and output encoding on all user-supplied data to prevent injection of malicious scripts. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in browsers. Conduct thorough security audits and penetration testing focused on XSS vectors within the CMS environment. Educate developers and administrators on secure coding practices, particularly regarding input sanitization and output encoding. Monitor logs and user activity for signs of exploitation attempts or unusual behavior. If upgrading is not immediately feasible, consider deploying Web Application Firewalls (WAFs) with custom rules to detect and block XSS payloads targeting HAX CMS endpoints. Finally, maintain an incident response plan to quickly address any detected compromise resulting from this vulnerability.