Ubuntu Linux today pushed out a new version of Linux kernel to fix serval local and remote security issues. A malicious CIFS server could cause a client system crash or possibly execute arbitrary code with kernel privileges. On SMP systems, a race condition existed in fcntl(). Local attackers could perform malicious locks, causing system crashes and leading to a denial of service. This security issue affects the following Ubuntu, Kubuntu, Edubuntu, and Xubuntu. releases:

=> Ubuntu 6.06 LTS
=> Ubuntu 7.04
=> Ubuntu 7.10

To fix this issue type the following two commands:
$ sudo apt-get update
$ sudo apt-get upgrade
You need to reboot your computer to effect the necessary changes, enter:
$ sudo reboot