In ImageMagick before 6.9.7-6 and 7.x before 7.0.4-6, the ReadMATImage function in coders/mat.c uses uninitialized data, which might allow remote attackers to obtain sensitive information from process memory.
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=870012
https://github.com/ImageMagick/ImageMagick/commit/51b0ae01709adc1e4a9245e158ef17b85a110960
https://github.com/ImageMagick/ImageMagick/issues/362
https://security.gentoo.org/glsa/201711-07
https://usn.ubuntu.com/3681-1/