=========================================================================Ubuntu Security Notice USN-2568-1
April 13, 2015

libx11, libxrender vulnerability
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 14.10
- Ubuntu 14.04 LTS
- Ubuntu 12.04 LTS

Summary:

libx11 could be made to crash or run programs if it processed specially
crafted data.

Software Description:
- libxrender: X11 Rendering Extension client library
- libx11: X11 client-side library

Details:

Abhishek Arya discovered that libX11 incorrectly handled memory in the
MakeBigReq macro. A remote attacker could use this issue to cause
applications to crash, resulting in a denial of service, or possibly
execute arbitrary code.

In addition, following the macro fix in libx11, a number of other packages
have also been rebuilt as security updates including libxrender, libxext,
libxi, libxfixes, libxrandr, libsdl1.2, libxv, libxp, and
xserver-xorg-video-vmware.

Update instructions:

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

Ubuntu 14.10:
  libxrender1                     1:0.9.8-1build0.14.10.1

Ubuntu 14.04 LTS:
  libxrender1                     1:0.9.8-1build0.14.04.1

Ubuntu 12.04 LTS:
  libx11-dev                      2:1.4.99.1-0ubuntu2.3
  libxrender1                     1:0.9.6-2ubuntu0.2

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

References:
  https://ubuntu.com/security/notices/USN-2568-1
  CVE-2013-7439

Package Information:
  https://launchpad.net/ubuntu/+source/libxrender/1:0.9.8-1build0.14.10.1
  https://launchpad.net/ubuntu/+source/libxrender/1:0.9.8-1build0.14.04.1
  https://launchpad.net/ubuntu/+source/libx11/2:1.4.99.1-0ubuntu2.3
  https://launchpad.net/ubuntu/+source/libxrender/1:0.9.6-2ubuntu0.2