The DNS packet parser in YADIFA before 2.2.6 does not check for the presence of infinite pointer loops, and thus it is possible to force it to enter an infinite loop. This can cause high CPU usage and makes the server unresponsive.
Created yadifa tracking bugs for this issue:
Affects: epel-all [bug 1494006]
Affects: fedora-all [bug 1494007]
Already fixed in updates