The WritePixelCachePixels function in ImageMagick 7.0.6-6 allows remote attackers to cause a denial of service (CPU consumption) via a crafted file.
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