=========================================================================Ubuntu Security Notice USN-4041-2
June 29, 2019

linux-lts-xenial, linux-aws, linux-azure update
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 14.04 ESM

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux-aws: Linux kernel for Amazon Web Services (AWS) systems
- linux-azure: Linux kernel for Microsoft Azure Cloud systems
- linux-lts-xenial: Linux hardware enablement kernel from Xenial for Trusty

Details:

USN-4041-1 provided updates for the Linux kernel in Ubuntu.
This update provides the corresponding updates for the Linux kernel
for Ubuntu 16.04 ESM.

USN-4017-2 fixed vulnerabilities in the Linux kernel.  Unfortunately,
the update introduced a regression that interfered with networking
applications that setup very low SO_SNDBUF values. This update fixes
the problem.

We apologize for the inconvenience.

Jonathan Looney discovered that the Linux kernel could be coerced into
segmenting responses into multiple TCP segments. A remote attacker could
construct an ongoing sequence of requests to cause a denial of service.
(CVE-2019-11479)

Update instructions:

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

Ubuntu 14.04 ESM:
  linux-image-4.15.0-1049-azure   4.15.0-1049.54~14.04.1
  linux-image-4.4.0-1048-aws      4.4.0-1048.52
  linux-image-4.4.0-154-generic   4.4.0-154.181~14.04.1
  linux-image-4.4.0-154-generic-lpae  4.4.0-154.181~14.04.1
  linux-image-4.4.0-154-lowlatency  4.4.0-154.181~14.04.1
  linux-image-4.4.0-154-powerpc-e500mc  4.4.0-154.181~14.04.1
  linux-image-4.4.0-154-powerpc-smp  4.4.0-154.181~14.04.1
  linux-image-4.4.0-154-powerpc64-emb  4.4.0-154.181~14.04.1
  linux-image-4.4.0-154-powerpc64-smp  4.4.0-154.181~14.04.1
  linux-image-aws                 4.4.0.1048.49
  linux-image-azure               4.15.0.1049.36
  linux-image-generic-lpae-lts-xenial  4.4.0.154.135
  linux-image-generic-lts-xenial  4.4.0.154.135
  linux-image-lowlatency-lts-xenial  4.4.0.154.135
  linux-image-powerpc-e500mc-lts-xenial  4.4.0.154.135
  linux-image-powerpc-smp-lts-xenial  4.4.0.154.135
  linux-image-powerpc64-emb-lts-xenial  4.4.0.154.135
  linux-image-powerpc64-smp-lts-xenial  4.4.0.154.135
  linux-image-virtual-lts-xenial  4.4.0.154.135

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-4041-2
  https://ubuntu.com/security/notices/USN-4041-1
  CVE-2019-11479, https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/SACKPanic