=========================================================================Ubuntu Security Notice USN-2858-1
January 05, 2016

linux vulnerability
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 15.10

Summary:

The system could be made to run programs as an administrator.

Software Description:
- linux: Linux kernel

Details:

Nathan Williams discovered that overlayfs in the Linux kernel incorrectly
handled setattr operations. A local unprivileged attacker could use this to
create files with administrative permission attributes and execute
arbitrary code with elevated privileges.

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 15.10:
  linux-image-4.2.0-23-generic    4.2.0-23.28
  linux-image-4.2.0-23-generic-lpae  4.2.0-23.28
  linux-image-4.2.0-23-lowlatency  4.2.0-23.28
  linux-image-4.2.0-23-powerpc-e500mc  4.2.0-23.28
  linux-image-4.2.0-23-powerpc-smp  4.2.0-23.28
  linux-image-4.2.0-23-powerpc64-emb  4.2.0-23.28
  linux-image-4.2.0-23-powerpc64-smp  4.2.0-23.28

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.
Unless you manually uninstalled the standard kernel metapackages
(e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual,
linux-powerpc), a standard system upgrade will automatically perform
this as well.

References:
  https://ubuntu.com/security/notices/USN-2858-1
  CVE-2015-8660

Package Information:
  https://launchpad.net/ubuntu/+source/linux/4.2.0-23.28