The ReadDCMImage function in coders\dcm.c in ImageMagick 7.0.6-1 has an integer signedness error leading to excessive memory consumption via a crafted DCM file.
https://usn.ubuntu.com/3681-1/
https://security.gentoo.org/glsa/201711-07
https://lists.debian.org/debian-lts-announce/2020/09/msg00007.html
https://lists.debian.org/debian-lts-announce/2019/05/msg00015.html