The remote host is missing an update to libgd2 announced via advisory USN-298-1.
A security issue affects the following Ubuntu releases:
Ubuntu 5.04 Ubuntu 5.10 Ubuntu 6.06 LTS
This advisory also applies to the corresponding versions of Kubuntu, Edubuntu, and Xubuntu.
Xavier Roche discovered that libgd's function for reading GIF image data did not sufficiently verify its validity. Specially crafted GIF images could cause an infinite loop which used up all available CPU resources. Since libgd is often used in PHP and Perl web applications, this could lead to a remote Denial of Service vulnerability.
Solution: The problem can be corrected by upgrading your system to the following package versions: