The remote host is missing an update to tiff announced via advisory USN-801-1.
Details follow:
Tielei Wang and Tom Lane discovered that the TIFF library did not correctly handle certain malformed TIFF images. If a user or automated system were tricked into processing a malicious image, an attacker could execute arbitrary code with the privileges of the user invoking the program.
Solution: The problem can be corrected by upgrading your system to the following package versions:
Ubuntu 6.06 LTS: libtiff4 3.7.4-1ubuntu3.6
Ubuntu 8.04 LTS: libtiff4 3.8.2-7ubuntu3.4
Ubuntu 8.10: libtiff4 3.8.2-11ubuntu0.8.10.3
Ubuntu 9.04: libtiff4 3.8.2-11ubuntu0.9.04.3
In general, a standard system upgrade is sufficient to effect the necessary changes.