Stored Cross-Site Scripting (XSS) in FacturaScripts, version 2025.61, caused by a lack of adequate validation or sanitisation of user input in the ‘city’ and ‘province’ fields in the ‘ListAlmacen’ endpoint. Successful exploitation of this vulnerability could allow an attacker to execute arbitrary JavaScript code in the victim’s browser (the application user) or to escalate privileges from a normal user to an administrator by executing specially crafted JavaScript code, thereby compromising the system’s confidentiality or hijacking the session (even with httpOnly cookies by extracting CSRF tokens).