Several security issues were fixed in the kernel.
Vince Weaver discovered a flaw in the perf subsystem of the Linux kernel on ARM platforms. A local user could exploit this flaw to gain privileges or cause a denial of service (system crash). (CVE-2013-4254)
27 September 2013
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in the kernel.
Vince Weaver discovered a flaw in the perf subsystem of the Linux kernel on ARM platforms. A local user could exploit this flaw to gain privileges or cause a denial of service (system crash). (CVE-2013-4254)
A memory leak was discovered in the user namespace facility of the Linux kernel. A local user could cause a denial of service (memory consumption) via the CLONE_NEWUSER unshare call. (CVE-2013-4205)
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
After a standard system update you need to reboot your computer to make all the necessary changes.
ATTENTION: Due to an unavoidable ABI change the kernel updates have been given a new version number, which requires you to recompile and reinstall all third party kernel modules you might have installed. If you use linux-restricted-modules, you have to update that package as well to get modules which work with the new kernel version. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-server, linux-powerpc), a standard system upgrade will automatically perform this as well.