A reflected cross-site scripting (XSS) vulnerability exists in the Moodle LMS Jmol plugin version 6.1 and prior via the data parameter in jsmol.php. The application fails to properly sanitize user input before embedding it into the HTTP response, allowing an attacker to execute arbitrary JavaScript in the victim's browser by crafting a malicious link. This can be used to hijack user sessions or manipulate page content. Exploitation evidence was observed by the Shadowserver Foundation on 2025-02-02 UTC.