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Gentoo Linux Security Advisory                           GLSA 200804-15
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                                            http://security.gentoo.org/
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  Severity: High
     Title: libpng: Execution of arbitrary code
      Date: April 15, 2008
      Bugs: #217047
        ID: 200804-15

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Synopsis
========

A vulnerability in libpng may allow for execution of arbitrary code in
certain applications that handle untrusted images.

Background
==========

libpng is a free ANSI C library used to process and manipulate PNG
images.

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

    -------------------------------------------------------------------
     Package            /   Vulnerable   /                  Unaffected
    -------------------------------------------------------------------
  1  media-libs/libpng      < 1.2.26-r1                   >= 1.2.26-r1

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

Tavis Ormandy of the Google Security Team discovered that libpng does
not handle zero-length unknown chunks in PNG files correctly, which
might lead to memory corruption in applications that call
png_set_read_user_chunk_fn() or png_set_keep_unknown_chunks().

Impact
======

A remote attacker could entice a user or automated system to process a
specially crafted PNG image in an application using libpng and possibly
execute arbitrary code with the privileges of the user running the
application. Note that processing of unknown chunks is disabled by
default in most PNG applications, but some such as ImageMagick are
affected.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All libpng users should upgrade to the latest version:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=media-libs/libpng-1.2.26-r1"

References
==========

  [ 1 ] CVE-2008-1382
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2008-1382

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

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

  http://security.gentoo.org/glsa/glsa-200804-15.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 2008 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