Ubuntu Security Notice USN-3468-3
31st October, 2017
A security issue affects these releases of Ubuntu and its
- Ubuntu 16.04 LTS
Several security issues were fixed in the Linux kernel.
– Linux kernel for Google Cloud Platform (GCP) systems
It was discovered that the KVM subsystem in the Linux kernel did not
properly bound guest IRQs. A local attacker in a guest VM could use this to
cause a denial of service (host system crash). (CVE-2017-1000252)
It was discovered that the Flash-Friendly File System (f2fs) implementation
in the Linux kernel did not properly validate superblock metadata. A local
attacker could use this to cause a denial of service (system crash) or
possibly execute arbitrary code. (CVE-2017-10663)
Anthony Perard discovered that the Xen virtual block driver did not
properly initialize some data structures before passing them to user space.
A local attacker in a guest VM could use this to expose sensitive
information from the host OS or other guest VMs. (CVE-2017-10911)
It was discovered that a use-after-free vulnerability existed in the POSIX
message queue implementation in the Linux kernel. A local attacker could
use this to cause a denial of service (system crash) or possibly execute
arbitrary code. (CVE-2017-11176)
Dave Chinner discovered that the XFS filesystem did not enforce that the
realtime inode flag was settable only on filesystems on a realtime device.
A local attacker could use this to cause a denial of service (system
The problem can be corrected by updating your system to the following
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.