CVE 2012-2088
Integer signedness error in the TIFFReadDirectory function in tif_dirread.c in libtiff 3.9.4 and earlier allows remote attackers to cause a denial of service (application crash) and possibly execute arbitrary code via a negative tile depth in a tiff image, which triggers an improper conversion between signed and unsigned types, leading to a heap-based buffer overflow.
See the 
CVE page on Mitre.org
for more details.
