USN-3220-1: Linux kernel vulnerability

8 March 2017

linux, linux-gke, linux-raspi2, linux-snapdragon vulnerability

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

  • Ubuntu 16.04 LTS


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

Software Description

  • linux - Linux kernel
  • linux-gke - Linux Kernel for Google Container Engine (GKE) systems
  • linux-raspi2 - Linux kernel for Raspberry Pi 2
  • linux-snapdragon - Linux kernel for Snapdragon Processors


Alexander Popov discovered that the N_HDLC line discipline implementation in the Linux kernel contained a double-free vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly gain administrative privileges.

Update instructions

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

Ubuntu 16.04 LTS
linux-image-4.4.0-1005-gke - 4.4.0-1005.6
linux-image-4.4.0-1046-raspi2 - 4.4.0-1046.53
linux-image-4.4.0-1050-snapdragon - 4.4.0-1050.54
linux-image-4.4.0-66-generic - 4.4.0-66.87
linux-image-4.4.0-66-generic-lpae - 4.4.0-66.87
linux-image-4.4.0-66-lowlatency - 4.4.0-66.87
linux-image-4.4.0-66-powerpc-e500mc - 4.4.0-66.87
linux-image-4.4.0-66-powerpc-smp - 4.4.0-66.87
linux-image-4.4.0-66-powerpc64-emb - 4.4.0-66.87
linux-image-4.4.0-66-powerpc64-smp - 4.4.0-66.87
linux-image-generic -
linux-image-generic-lpae -
linux-image-gke -
linux-image-lowlatency -
linux-image-powerpc-e500mc -
linux-image-powerpc-smp -
linux-image-powerpc64-emb -
linux-image-powerpc64-smp -
linux-image-raspi2 -
linux-image-snapdragon -

To update your system, please follow these instructions:

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.