Cross-site scripting (XSS) vulnerability in web/springframework/security/SecurityAuthenticationEventOnmsEventBuilder.java in OpenNMS 1.8.x before 1.8.17, 1.9.93 and earlier, and 1.10.x before 1.10.1 allows remote attackers to inject arbitrary web script or HTML via the Username field, related to login.
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.