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Gentoo Linux Security Advisory                           GLSA 200607-06
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                                            http://security.gentoo.org/
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  Severity: Normal
     Title: libpng: Buffer overflow
      Date: July 19, 2006
      Bugs: #138433, #138672
        ID: 200607-06

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Synopsis
========

A buffer overflow has been found in the libpng library that could lead
to the execution of arbitrary code.

Background
==========

libpng is an open, extensible image format library, with lossless
compression.

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

    -------------------------------------------------------------------
     Package                  /  Vulnerable  /              Unaffected
    -------------------------------------------------------------------
  1  libpng                       < 1.2.12                   >= 1.2.12
  2  emul-linux-x86-baselibs       < 2.5.1                    >= 2.5.1
    -------------------------------------------------------------------
     # Package 2 [app-emulation/emul-linux-x86-baselibs] only applies
       to AMD64 users.

     NOTE: Any packages listed without architecture tags apply to all
           architectures...
    -------------------------------------------------------------------
     2 affected packages
    -------------------------------------------------------------------

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

In pngrutil.c, the function png_decompress_chunk() allocates
insufficient space for an error message, potentially overwriting stack
data, leading to a buffer overflow.

Impact
======

By enticing a user to load a maliciously crafted PNG image, an attacker
could execute arbitrary code with the rights of the user, or crash the
application using the libpng library, such as the
emul-linux-x86-baselibs.

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-1.2.12"

All AMD64 emul-linux-x86-baselibs users should also upgrade to the
latest version:

    # emerge --sync
    # emerge --ask --oneshot --verbose
">=app-emulation/emul-linux-x86-baselibs-2.5.1"

References
==========

  [ 1 ] libpng Changelog

http://heanet.dl.sourceforge.net/sourceforge/libpng/libpng-1.2.12-README.txt
  [ 2 ] CVE-2006-3334
        http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-3334

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

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

  http://security.gentoo.org/glsa/glsa-200607-06.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 2006 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