The LZW decompressor in the gif2tiff tool in libtiff 4.0.3 and earlier allows context-dependent attackers to cause a denial of service (out-of-bounds write and crash) or possibly execute arbitrary code via a crafted GIF image.
http://bugzilla.maptools.org/show_bug.cgi?id=2452
http://rhn.redhat.com/errata/RHSA-2014-0223.html
https://bugzilla.redhat.com/show_bug.cgi?id=996468
https://github.com/vadz/libtiff/commit/ce6841d9e41d621ba23cf18b190ee6a23b2cc833