ImageMagick 6.7.5-7 and earlier allows remote attackers to cause a denial of service (infinite loop and hang) via a crafted image whose IFD contains IOP tags that all reference the beginning of the IDF.
http://www.securitytracker.com/id?1027032
http://www.securityfocus.com/bid/51957
http://www.imagemagick.org/discourse-server/viewtopic.php?f=4&t=20286
http://www.gentoo.org/security/en/glsa/glsa-201203-09.xml
http://www.debian.org/security/2012/dsa-2427
http://ubuntu.com/usn/usn-1435-1