The _TIFFVGetField function in tif_dir.c in libtiff 4.0.6 allows attackers to cause a denial of service (invalid memory write and crash) or possibly have unspecified other impact via crafted field data in an extension tag in a TIFF image. http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-7554
