The IPv6 parser in tcpdump before 4.9.2 has a buffer over-read in print-ip6.c:ip6_print().
https://support.apple.com/HT208221
https://security.gentoo.org/glsa/201709-23
https://github.com/the-tcpdump-group/tcpdump/commit/66df248b49095c261138b5a5e34d341a6bf9ac7f
https://access.redhat.com/errata/RHEA-2018:0705
http://www.tcpdump.org/tcpdump-changes.txt