The remote host is missing an update to gnupg announced via advisory USN-393-1.
A security issue affects the following Ubuntu releases:
Ubuntu 5.10 Ubuntu 6.06 LTS Ubuntu 6.10
This advisory also applies to the corresponding versions of Kubuntu, Edubuntu, and Xubuntu.
Details follow:
Tavis Ormandy discovered that gnupg was incorrectly using the stack. If a user were tricked into processing a specially crafted message, an attacker could execute arbitrary code with the user's privileges.
Solution: The problem can be corrected by upgrading your system to the following package versions:
Ubuntu 5.10: gnupg 1.4.1-1ubuntu1.6
Ubuntu 6.06 LTS: gnupg 1.4.2.2-1ubuntu2.4
Ubuntu 6.10: gnupg 1.4.3-2ubuntu3.2
In general, a standard system upgrade is sufficient to effect the necessary changes.