USN-571-1: vulnerabilities

Ubuntu Security Notice USN-571-1

17th January, 2008

libxfont, xorg-server vulnerabilities

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

  • Ubuntu 7.10
  • Ubuntu 7.04
  • Ubuntu 6.10
  • Ubuntu 6.06 LTS

Software description

  • libxfont
  • xorg-server


Multiple overflows were discovered in the XFree86-Misc, XInput-Misc,
TOG-CUP, EVI, and MIT-SHM extensions which did not correctly validate
function arguments. An authenticated attacker could send specially
crafted requests and gain root privileges. (CVE-2007-5760, CVE-2007-6427,
CVE-2007-6428, CVE-2007-6429)

It was discovered that the server did not use user privileges when
attempting to open security policy files. Local attackers could exploit
this to probe for files in directories they would not normally be able
to access. (CVE-2007-5958)

It was discovered that the PCF font handling code did not correctly
validate the size of fonts. An authenticated attacker could load a
specially crafted font and gain additional privileges. (CVE-2008-0006)

Update instructions

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

Ubuntu 7.10:
libxfont1 1:1.3.0-0ubuntu1.1
xserver-xorg-core 2:
Ubuntu 7.04:
libxfont1 1:1.2.7-1ubuntu1.1
xserver-xorg-core 2:1.2.0-3ubuntu8.1
Ubuntu 6.10:
libxfont1 1:1.2.0-0ubuntu3.2
xserver-xorg-core 1:1.1.1-0ubuntu12.3
Ubuntu 6.06 LTS:
libxfont1 1:1.0.0-0ubuntu3.4
xserver-xorg-core 1:1.0.2-0ubuntu10.8

To update your system, please follow these instructions:

After a standard system upgrade you need to restart your session to effect
the necessary changes.


CVE-2007-5760, CVE-2007-5958, CVE-2007-6427, CVE-2007-6428, CVE-2007-6429, CVE-2008-0006