In ImageMagick before 6.9.9-3 and 7.x before 7.0.6-3, there is a missing NULL check in the ReadMATImage function in coders/mat.c, leading to a denial of service (assertion failure and application exit) in the DestroyImageInfo function in MagickCore/image.c.
https://lists.debian.org/debian-lts-announce/2020/09/msg00007.html
https://lists.debian.org/debian-lts-announce/2019/05/msg00015.html
https://github.com/ImageMagick/ImageMagick/issues/598
https://github.com/ImageMagick/ImageMagick/commit/e5c063a1007506ba69e97a35effcdef944421c89