ReadGIFImage in coders/gif.c in ImageMagick 7.0.6-1 and GraphicsMagick 1.3.26 leaves the palette uninitialized when processing a GIF file that has neither a global nor local palette. If the affected product is used as a library loaded into a process that operates on interesting data, this data sometimes can be leaked via the uninitialized palette.
github.com/ImageMagick/ImageMagick/commit/9fd10cf630832b36a588c1545d8736539b2f1fb5
github.com/ImageMagick/ImageMagick/issues/592
github.com/neex/gifoeb
lists.debian.org/debian-lts-announce/2018/08/msg00002.html
usn.ubuntu.com/3681-1/
usn.ubuntu.com/4232-1/
www.debian.org/security/2017/dsa-4032
www.debian.org/security/2017/dsa-4040
www.debian.org/security/2018/dsa-4321