=========================================================================Ubuntu Security Notice USN-3758-1
August 30, 2018

libx11 vulnerabilities
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS

Summary:

Several security issues were fixed in libx11.

Software Description:
- libx11: X11 client-side library

Details:

Tobias Stoeckmann discovered that libx11 incorrectly handled certain
images. An attacker could possibly use this issue to access sensitive
information (CVE-2016-7942)

Tobias Stoeckmann discovered that libx11 incorrectly handled certain
inputs. An attacker could possibly use this issue to access sensitive
information. (CVE-2016-7943)

It was discovered that libx11 incorrectly handled certain inputs.
An attacker could possibly use this issue to cause a denial of service.
(CVE-2018-14598, CVE-2018-14599, CVE-2018-14600)

Update instructions:

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

Ubuntu 18.04 LTS:
  libx11-6                        2:1.6.4-3ubuntu0.1
  libx11-dev                      2:1.6.4-3ubuntu0.1

Ubuntu 16.04 LTS:
  libx11-6                        2:1.6.3-1ubuntu2.1
  libx11-dev                      2:1.6.3-1ubuntu2.1

Ubuntu 14.04 LTS:
  libx11-6                        2:1.6.2-1ubuntu2.1
  libx11-dev                      2:1.6.2-1ubuntu2.1

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

References:
  https://ubuntu.com/security/notices/USN-3758-1
  CVE-2016-7942, CVE-2016-7943, CVE-2018-14598, CVE-2018-14599,
  CVE-2018-14600

Package Information:
  https://launchpad.net/ubuntu/+source/libx11/2:1.6.4-3ubuntu0.1
  https://launchpad.net/ubuntu/+source/libx11/2:1.6.3-1ubuntu2.1
  https://launchpad.net/ubuntu/+source/libx11/2:1.6.2-1ubuntu2.1