In Wireshark 2.6.0, 2.4.0 to 2.4.6, and 2.2.0 to 2.2.14, the LTP dissector and other dissectors could consume excessive memory. This was addressed in epan/tvbuff.c by rejecting negative lengths.
http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00027.html
https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=14678
https://lists.debian.org/debian-lts-announce/2019/01/msg00010.html