Masa CMS is an open source Enterprise Content Management platform. Versions 7.2.8 and below, 7.3.1 through 7.3.13, 7.4.0-alpha.1 through 7.4.8 and 7.5.0 through 7.5.1 are vulnerable to XSS when an unsanitized value of the ajax URL query parameter is directly included within the <head> section of the HTML page. An attacker can execute arbitrary scripts in the context of the user's session, potentially leading to Session Hijacking, Data Theft, Defacement and Malware Distribution. This issue is fixed in versions 7.5.2, 7.4.9, 7.3.14, and 7.2.9. To work around this issue, configure a Web Application Firewall (WAF) rule (e.g., ModSecurity) to block requests containing common XSS payload characters in the ajax query parameter. Alternatively, implement server-side sanitization using middleware to strip or escape dangerous characters from the ajax parameter before it reaches the vulnerable rendering logic.