USN-2803-1: Linux kernel vulnerability

10 November 2015

linux vulnerability

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

  • Ubuntu 15.10

Summary

The system could be made to crash under certain conditions.

Software Description

  • linux - Linux kernel

Details

Ben Serebrin discovered that the KVM hypervisor implementation in the Linux kernel did not properly catch Alignment Check exceptions. An attacker in a guest virtual machine could use this to cause a denial of service (system crash) in the host OS.

Update instructions

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

Ubuntu 15.10
linux-image-4.2.0-18-generic - 4.2.0-18.22
linux-image-4.2.0-18-generic-lpae - 4.2.0-18.22
linux-image-4.2.0-18-lowlatency - 4.2.0-18.22
linux-image-4.2.0-18-powerpc-e500mc - 4.2.0-18.22
linux-image-4.2.0-18-powerpc-smp - 4.2.0-18.22
linux-image-4.2.0-18-powerpc64-emb - 4.2.0-18.22
linux-image-4.2.0-18-powerpc64-smp - 4.2.0-18.22

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.

References