Heap-based buffer overflow in the ReadPCXImage function in the PCX coder in coders/pcx.c in (1) ImageMagick 6.2.4-5 and 6.2.8-0 and (2) GraphicsMagick (aka gm) 1.1.7 allows user-assisted remote attackers to cause a denial of service (crash) or possibly execute arbitrary code via a crafted .pcx file that triggers incorrect memory allocation for the scanline array, leading to memory corruption.