Cross-site scripting (XSS) vulnerability in Nagios XI before 5.5.11 allows attackers to inject arbitrary web script or HTML via the xiwindow parameter.
https://www.nagios.com/products/security/
https://www.nagios.com/downloads/nagios-xi/change-log/
http://packetstormsecurity.com/files/152496/Nagios-XI-5.5.10-XSS-Remote-Code-Execution.html