In Wireshark 2.6.0 to 2.6.1, 2.4.0 to 2.4.7, and 2.2.0 to 2.2.15, the DICOM dissector could go into a large or infinite loop. This was addressed in epan/dissectors/packet-dcm.c by preventing an offset overflow.
http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00027.html
https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=14742
https://lists.debian.org/debian-lts-announce/2018/07/msg00045.html