The AcquireResampleFilterThreadSet function in magick/resample-private.h in ImageMagick 7.0.7-4 mishandles failed memory allocation, which allows remote attackers to cause a denial of service (NULL Pointer Dereference in DistortImage in MagickCore/distort.c, and application crash) via unspecified vectors.
https://usn.ubuntu.com/3681-1/
https://lists.debian.org/debian-lts-announce/2020/09/msg00007.html
https://lists.debian.org/debian-lts-announce/2019/05/msg00015.html