The following updates has been released for Ubuntu Linux:

LSN-0056-1: Linux kernel vulnerability
USN-4134-2: IBus regression

LSN-0056-1: Linux kernel vulnerability

==========================================================================
Kernel Live Patch Security Notice 0056-1
September 20, 2019

linux vulnerability
==========================================================================

A security issue affects these releases of Ubuntu:

| Series | Base kernel | Arch | flavors |
|------------------+--------------+----------+------------------|
| Ubuntu 18.04 LTS | 4.15.0 | amd64 | generic |
| Ubuntu 18.04 LTS | 4.15.0 | amd64 | lowlatency |
| Ubuntu 16.04 LTS | 4.4.0 | amd64 | generic |
| Ubuntu 16.04 LTS | 4.4.0 | amd64 | lowlatency |
| Ubuntu 16.04 LTS | 4.15.0 | amd64 | generic |
| Ubuntu 16.04 LTS | 4.15.0 | amd64 | lowlatency |

Summary:

Several security issues were fixed in the kernel.

Software Description:
- linux: Linux kernel

Details:

Peter Pi discovered a buffer overflow in the virtio network backend
(vhost_net) implementation in the Linux kernel. An attacker in a guest may
be able to use this to cause a denial of service (host OS crash) or
possibly execute arbitrary code in the host OS. (CVE-2019-14835)

Update instructions:

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

| Kernel | Version | flavors |
|--------------------------+----------+--------------------------|
| 4.4.0-148.174 | 56.1 | lowlatency, generic |
| 4.4.0-150.176 | 56.1 | generic, lowlatency |
| 4.4.0-151.178 | 56.1 | lowlatency, generic |
| 4.4.0-154.181 | 56.1 | lowlatency, generic |
| 4.4.0-157.185 | 56.1 | lowlatency, generic |
| 4.4.0-159.187 | 56.1 | lowlatency, generic |
| 4.4.0-161.189 | 56.1 | lowlatency, generic |
| 4.15.0-50.54 | 56.1 | generic, lowlatency |
| 4.15.0-50.54~16.04.1 | 56.1 | generic, lowlatency |
| 4.15.0-51.55 | 56.1 | generic, lowlatency |
| 4.15.0-51.55~16.04.1 | 56.1 | generic, lowlatency |
| 4.15.0-52.56 | 56.1 | lowlatency, generic |
| 4.15.0-52.56~16.04.1 | 56.1 | generic, lowlatency |
| 4.15.0-54.58 | 56.1 | generic, lowlatency |
| 4.15.0-54.58~16.04.1 | 56.1 | generic, lowlatency |
| 4.15.0-55.60 | 56.1 | generic, lowlatency |
| 4.15.0-58.64 | 56.1 | generic, lowlatency |
| 4.15.0-58.64~16.04.1 | 56.1 | lowlatency, generic |
| 4.15.0-60.67 | 56.1 | lowlatency, generic |
| 4.15.0-60.67~16.04.1 | 56.1 | generic, lowlatency |
| 4.15.0-62.69 | 56.1 | generic, lowlatency |
| 4.15.0-62.69~16.04.1 | 56.1 | lowlatency, generic |

Support Information:

Kernels older than the levels listed below do not receive livepatch
updates. Please upgrade your kernel as soon as possible.

| Series | Version | Flavors |
|------------------+------------------+--------------------------|
| Ubuntu 18.04 LTS | 4.15.0-50 | generic lowlatency |
| Ubuntu 16.04 LTS | 4.15.0-50 | generic lowlatency |
| Ubuntu 14.04 LTS | 4.4.0-148 | generic lowlatency |
| Ubuntu 16.04 LTS | 4.4.0-148 | generic lowlatency |

References:
CVE-2019-14835

USN-4134-2: IBus regression

==========================================================================
Ubuntu Security Notice USN-4134-2
September 23, 2019

ibus regression
==========================================================================

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

- Ubuntu 19.04
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

USN 4134-1 introduced a regression in IBus.

Software Description:
- ibus: Intelligent Input Bus - core

Details:

USN-4134-1 fixed a vulnerability in IBus. The security fix introduced a
regression when being used with Qt applications. This update reverts the
security fix pending further investigation.

Original advisory details:

Simon McVittie discovered that IBus did not enforce appropriate access
controls on its private D-Bus socket. A local unprivileged user who
discovers the IBus socket address of another user could exploit this to
capture the key strokes of the other user.

Update instructions:

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

Ubuntu 19.04:
ibus 1.5.19-1ubuntu2.2

Ubuntu 18.04 LTS:
ibus 1.5.17-3ubuntu5.2

Ubuntu 16.04 LTS:
ibus 1.5.11-1ubuntu2.3

After a standard system update you need to reboot your computer to make
all the necessary changes.

References:
https://usn.ubuntu.com/4134-2
https://usn.ubuntu.com/4134-1
https://launchpad.net/bugs/1844853

Package Information:
https://launchpad.net/ubuntu/+source/ibus/1.5.19-1ubuntu2.2
https://launchpad.net/ubuntu/+source/ibus/1.5.17-3ubuntu5.2
https://launchpad.net/ubuntu/+source/ibus/1.5.11-1ubuntu2.3