A memory allocation failure was discovered in the ReadPNMImage function in coders/pnm.c in GraphicsMagick 1.3.26. The vulnerability causes a big memory allocation, which may lead to remote denial of service in the MagickRealloc function in magick/memory.c.
https://usn.ubuntu.com/4206-1/
http://www.securityfocus.com/bid/100556
http://hg.code.sf.net/p/graphicsmagick/code/rev/3bbf7a13643d