In Wireshark 2.6.0 to 2.6.1 and 2.4.0 to 2.4.7, the CoAP protocol dissector could crash. This was addressed in epan/dissectors/packet-coap.c by properly checking for a NULL condition.
lists.opensuse.org/opensuse-security-announce/2020-03/msg00027.html
www.securityfocus.com/bid/104847
www.securitytracker.com/id/1041608
bugs.wireshark.org/bugzilla/show_bug.cgi?id=14966
code.wireshark.org/review/gitweb?p=wireshark.git%3Ba=commit%3Bh=81ce5fcb3e37a0aaeb7532f7a2a09366f16fa310
www.wireshark.org/security/wnpa-sec-2018-42.html