The remote host is missing an update to librpcsecgss announced via advisory USN-511-1.
A security issue affects the following Ubuntu releases:
Ubuntu 6.06 LTS Ubuntu 6.10 Ubuntu 7.04
This advisory also applies to the corresponding versions of Kubuntu, Edubuntu, and Xubuntu.
Details follow:
It was discovered that the libraries handling RPCSEC_GSS did not correctly validate the size of certain packet structures. An unauthenticated remote user could send a specially crafted request and execute arbitrary code with root privileges.
Solution: The problem can be corrected by upgrading your system to the following package versions: