ImageMagick: excessive iteration in the DecodeLabImage and EncodeLabImage functions in coders/tiff.c

ImageMagick 7.0.7-26 Q16 has excessive iteration in the DecodeLabImage and EncodeLabImage functions coders/tiff.c, which results in a hang tens of minutes with a tiny PoC file. Remote attackers could leverage this vulnerability to cause a denial of service via a crafted tiff file...