This indicates an attack attempt to exploit a Code Injection Vulnerability in Nagios Enterprises Nagios XI.
A remote, authenticated attacker can exploit this vulnerability by sending a crafted request to the autodiscovery component. Successful exploitation results in the execution of arbitrary commands as the apache user.
Nagios Enterprises Nagios XI prior to 5.5.11
System Compromise: Remote attackers can gain control of vulnerable systems.
Apply the most recent upgrade or patch from the vendor.