Null pointer dereference when handling TIFF images.
https://github.com/ImageMagick/ImageMagick/commit/ad86bdfef9e22db10d54e5d414f7d44cf13a6e95 fixed in -18, see bug 727444
Let's just do it in the CVE'd bug. *** This bug has been marked as a duplicate of bug 727444 ***