This indicates an attack attempt to exploit a Cross-Site Scripting Vulnerability in Nagios Enterprises Nagios XI.
This vulnerability is due to insufficient validation of the parameters in the vulnerable application. A remote attacker can exploit this vulnerability by enticing a target user into clicking a malicious link. Successful exploitation could result in the execution of script code in security context of the target user's browser.
Nagios Enterprises Nagios XI prior to 5.6.10
System Compromise: Remote attackers can execute arbitrary script code in the context of the affected application.
Apply the most recent upgrade or patch from the vendor.