The ReadVIFFImage function in coders/viff.c in ImageMagick 7.0.6-6 allows remote attackers to cause a denial of service (memory consumption) via a crafted VIFF file.
https://github.com/ImageMagick/ImageMagick/issues/653
https://lists.debian.org/debian-lts-announce/2019/05/msg00015.html
https://lists.debian.org/debian-lts-announce/2020/09/msg00007.html