In ImageMagick 7.0.7-23 Q16 x86_64 2018-01-24, there is a heap-based buffer over-read in ReadSUNImage in coders/sun.c, which allows attackers to cause a denial of service (application crash in SetGrayscaleImage in MagickCore/quantize.c) via a crafted SUN image file.
https://github.com/ImageMagick/ImageMagick/issues/956
https://lists.debian.org/debian-lts-announce/2018/05/msg00012.html
https://lists.debian.org/debian-lts-announce/2018/06/msg00004.html