[ GLSA 200710-16 ] X.Org X server: Composite local privilege escalation

[Pierre-Yves Rofes <py () gentoo org>]

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Gentoo Linux Security Advisory                           GLSA 200710-16
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                                            http://security.gentoo.org/
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  Severity: High
     Title: X.Org X server: Composite local privilege escalation
      Date: October 14, 2007
      Bugs: #191964
        ID: 200710-16

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Synopsis
========

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

Background
==========

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

Affected packages
=================

    -------------------------------------------------------------------
     Package               /   Vulnerable   /               Unaffected
    -------------------------------------------------------------------
  1  x11-base/xorg-server     < 1.3.0.0-r1               >= 1.3.0.0-r1

Description
===========

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.

Impact
======

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

Workaround
==========

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.

Resolution
==========

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

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=x11-base/xorg-server-1.3.0.0-r1"

References
==========

  [ 1 ] CVE-2007-4730
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-4730

Availability
============

This GLSA and any updates to it are available for viewing at
the Gentoo Security Website:

  http://security.gentoo.org/glsa/glsa-200710-16.xml

Concerns?
=========

Security is a primary focus of Gentoo Linux and ensuring the
confidentiality and security of our users machines is of utmost
importance to us. Any security concerns should be addressed to
security () gentoo org or alternatively, you may file a bug at
http://bugs.gentoo.org.

License
=======

Copyright 2007 Gentoo Foundation, Inc; referenced text
belongs to its owner(s).

The contents of this document are licensed under the
Creative Commons - Attribution / Share Alike license.

http://creativecommons.org/licenses/by-sa/2.5
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