Heap-based buffer overflow in the CalcMinMax function in coders/mat.c in
ImageMagick before 6.9.4-0 allows remote attackers to cause a denial of
service (out-of-bounds read and application crash) via a crafted mat file.
Fixed by upstream since 188.8.131.52. Landed in Gentoo via bf1360d003a494888c306a9b8ae00452861d13f9 in 184.108.40.206. Current stable version in Gentoo repository is 220.127.116.11. All done.