The remote host is missing an update to tar announced via advisory USN-506-1.
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:
Dmitry V. Levin discovered that tar did not correctly detect the .. file path element when unpacking archives. If a user or an automated system were tricked into unpacking a specially crafted tar file, arbitrary files could be overwritten with user privileges.
Solution: The problem can be corrected by upgrading your system to the following package versions:
Ubuntu 6.06 LTS: tar 1.15.1-2ubuntu2.2
Ubuntu 6.10: tar 1.15.91-2ubuntu0.4
Ubuntu 7.04: tar 1.16-2ubuntu0.1
In general, a standard system upgrade is sufficient to effect the necessary changes.