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X.Org X server: Composite local privilege escalation


1.  Gentoo Linux Security Advisory

Version Information

Advisory Reference GLSA 200710-16 / X.Org
Release Date October 14, 2007
Latest Revision October 14, 2007: 01
Impact high
Exploitable local
Package Vulnerable versions Unaffected versions Architecture(s)
x11-base/xorg-server < >= All supported architectures

Related bugreports: #191964


A vulnerability has been discovered in the Composite extension of the X.Org X server, allowing for a local privilege escalation.

2.  Impact Information


The X Window System is a graphical windowing system based on a client/server model.


Aaron Plattner discovered a buffer overflow in the compNewPixmap() function when copying data from a large pixel depth pixmap into a smaller pixel depth pixmap.


A local attacker could execute arbitrary code with the privileges of the user running the X server, typically root.

3.  Resolution Information


Disable the Composite extension by setting ' Option "Composite" "disable" ' in the Extensions section of xorg.conf.

Note: This could affect the functionality of some applications.


All X.Org X server users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=x11-base/xorg-server-"

4.  References


Page updated October 14, 2007

Summary: This is a Gentoo Linux Security Advisory

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