The ISAKMP parser in tcpdump before 4.9.2 has a buffer over-read in print-isakmp.c:isakmp_rfc3948_print().
https://support.apple.com/HT208221
https://security.gentoo.org/glsa/201709-23
https://github.com/the-tcpdump-group/tcpdump/commit/f76e7feb41a4327d2b0978449bbdafe98d4a3771
https://github.com/the-tcpdump-group/tcpdump/commit/4e430c6b0d8b7e77c7abca7e7afb0c3e727502f2
https://access.redhat.com/errata/RHEA-2018:0705
http://www.tcpdump.org/tcpdump-changes.txt