A security vulnerability that was discovered in the Linux kernel affecting the Ubuntu 12.10 LTS (Quantal Quetzal) operating system, was announced by Canonical.
Fox example, a flaw in the Linux kernel's KVM (Kernel-based virtual machine) subsystem's handling of the XSAVE CPU feature. On hosts without the XSAVE CPU feature, using qemu userspace, an unprivileged local attacker could exploit this flaw to crash the system.
The security flaws can be fixed if you upgrade your system(s) to the linux-image-3.5.0-22 (3.5.0-22.34).
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.