In Wireshark 3.0.0 to 3.0.3 and 2.6.0 to 2.6.10, the Gryphon dissector could go into an infinite loop. This was addressed in plugins/epan/gryphon/packet-gryphon.c by checking for a message length of zero.
https://www.wireshark.org/security/wnpa-sec-2019-21.html
https://lists.debian.org/debian-lts-announce/2021/02/msg00008.html
https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=16020
http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00027.html