An Invalid Address dereference was discovered in TIFFWriteDirectoryTagTransferfunction in libtiff/tif_dirwrite.c in LibTIFF 4.0.10, affecting the cpSeparateBufToContigBuf function in tiffcp.c. Remote attackers could leverage this vulnerability to cause a denial-of-service via a crafted tiff file. This is different from CVE-2018-12900.