ImageMagick 7.0.8-50 Q16 has a heap-based buffer over-read at MagickCore/threshold.c in AdaptiveThresholdImage because a height of zero is mishandled.
https://www.debian.org/security/2020/dsa-4712
https://usn.ubuntu.com/4192-1/
https://lists.debian.org/debian-lts-announce/2020/08/msg00030.html
https://lists.debian.org/debian-lts-announce/2019/08/msg00021.html
https://github.com/ImageMagick/ImageMagick6/commit/35c7032723d85eee7318ff6c82f031fa2666b773
https://github.com/ImageMagick/ImageMagick/issues/1609
https://github.com/ImageMagick/ImageMagick/commit/604588fc35c7585abb7a9e71f69bb82e4389fefc
http://lists.opensuse.org/opensuse-security-announce/2019-08/msg00069.html