USN-1990-1: X.Org X server vulnerabilities

Ubuntu Security Notice USN-1990-1

17th October, 2013

xorg-server, xorg-server-lts-quantal, xorg-server-lts-raring vulnerabilities

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

  • Ubuntu 13.04
  • Ubuntu 12.10
  • Ubuntu 12.04 LTS

Summary

The X.Org X server could be made to crash or run programs as an administrator if it received specially crafted input.

Software description

  • xorg-server - X.Org X11 server
  • xorg-server-lts-quantal - X.Org X11 server
  • xorg-server-lts-raring - X.Org X11 server

Details

Pedro Ribeiro discovered that the X.Org X server incorrectly handled
memory operations when handling ImageText requests. An attacker could use
this issue to cause X.Org to crash, or to possibly execute arbitrary code.
(CVE-2013-4396)

It was discovered that non-root X.Org X servers such as Xephyr incorrectly
used cached xkb files. A local attacker could use this flaw to cause a xkb
cache file to be loaded by another user, resulting in a denial of service.
(CVE-2013-1056)

Update instructions

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

Ubuntu 13.04:
xserver-xorg-core 2:1.13.3-0ubuntu6.2
Ubuntu 12.10:
xserver-xorg-core 2:1.13.0-0ubuntu6.4
Ubuntu 12.04 LTS:
xserver-xorg-core-lts-quantal 2:1.13.0-0ubuntu6.1~precise4
xserver-xorg-core 2:1.11.4-0ubuntu10.14
xserver-xorg-core-lts-raring 2:1.13.3-0ubuntu6~precise3

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

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

References

CVE-2013-1056, CVE-2013-4396