The remote host is missing an update to tiff announced via advisory DSA 617-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20617-1

infamous41md discovered a problem in libtiff, the Tag Image File Format library for processing TIFF graphics files. Upon reading a TIFF file it is possible to allocate a zero sized buffer and write to it which would lead to the execution of arbitrary code. For the stable distribution (woody) this problem has been fixed in version 3.5.5-6woody2. For the unstable distribution (sid) this problem has been fixed in version 3.6.1-4. We recommend that you upgrade your libtiff packages immediately.