The putagreytile function in tif_getimage.c in LibTIFF 4.0.7 has a left-shift undefined behavior issue, which might allow remote attackers to cause a denial of service (application crash) or possibly have unspecified other impact via a crafted image.
https://usn.ubuntu.com/3602-1/
https://security.gentoo.org/glsa/201709-27
http://www.securityfocus.com/bid/97510