The remote host is missing an update to firefox announced via advisory USN-645-2.
A security issue affects the following Ubuntu releases:
Ubuntu 6.06 LTS
This advisory also applies to the corresponding versions of Kubuntu, Edubuntu, and Xubuntu.
Details follow:
USN-645-1 fixed vulnerabilities in Firefox and xulrunner for Ubuntu 7.04, 7.10 and 8.04 LTS. This provides the corresponding update for Ubuntu 6.06 LTS.
Solution: The problem can be corrected by upgrading your system to the following package versions: