I just released NSCA 2.7.2 today to fix a possible bug with a multi-process NSCA daemon not accepting new clients and eating CPU due to the untimely death of child processes. The patch was pretty old (over a year), but I missed it until another user brought it to my attention. Get the latest version of NSCA here.
Nagios Update: XI 5.6.6
Nagios XI update 5.6.6 is now released! This update resolves a number of minor bugs and one security vulnerability fix. This version also includes improvements