A security vulnerability that was discovered in the Linux kernel affecting the Ubuntu 12.10 LTS (Quantal Quetzal) and Ubuntu 12.04 (Precise Pangolin) operating systems, was announced by Canonical.This is the kernel vulnerability found in the Linux kernel packages: CVE-2012-5517. The system's firewall could be bypassed by a remote attacker.
A flaw was discovered in the Linux kernel's handling of new hot-plugged memory. An unprivileged local user could exploit this flaw to cause a denial of service by crashing the system.
The security flaws can be fixed if you upgrade your system(s) to the linux-image-3.5.0-21 (3.5.0-21.32).
Don't forget to reboot your computer after the upgrade!
ATTENTION: Due to an unavoidable ABI change, the kernel packages have a new version number, which will force you to reinstall and recompile all third-party kernel modules you might have installed. Moreover, if you use the linux-restricted-modules package, you have to update it as well to get modules that work with the new Linux kernel version.