The DNS parser in tcpdump before 4.9.2 could enter an infinite loop due to a bug in print-domain.c:ns_print().
https://support.apple.com/HT208221
https://security.gentoo.org/glsa/201709-23
https://github.com/the-tcpdump-group/tcpdump/commit/3a76fd7c95fced2c2f8c8148a9055c3a542eff29
https://access.redhat.com/errata/RHEA-2018:0705
http://www.tcpdump.org/tcpdump-changes.txt