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Gentoo Linux Security Advisory                           GLSA 200405-06
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                                            https://security.gentoo.org/
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  Severity: Normal
     Title: libpng denial of service vulnerability
      Date: May 14, 2004
      Bugs: #49887
        ID: 200405-06

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Synopsis
=======
A bug in the libpng library can be abused to crash programs making use
of that library to decode PNG images.

Background
=========
libpng is a standard library used to process PNG (Portable Network
Graphics) images.

Affected packages
================
    -------------------------------------------------------------------
     Package            /   Vulnerable   /                  Unaffected
    -------------------------------------------------------------------
  1  media-libs/libpng      <= 1.2.5-r4                    >= 1.2.5-r5

Description
==========
libpng provides two functions (png_chunk_error and png_chunk_warning)
for default error and warning messages handling. These functions do not
perform proper bounds checking on the provided message, which is
limited to 64 bytes. Programs linked against this library may crash
when handling a malicious PNG image.

Impact
=====
This vulnerability could be used to crash various programs using the
libpng library, potentially resulting in a denial of service attack on
vulnerable daemon processes.

Workaround
=========
There is no known workaround at this time. All users are advised to
upgrade to the latest available version of libpng.

Resolution
=========
All users of libpng should upgrade to the latest stable version:

    # emerge sync

    # emerge -pv ">=media-libs/libpng-1.2.5-r5"
    # emerge ">=media-libs/libpng-1.2.5-r5"

You should also run revdep-rebuild to rebuild any packages that depend
on older versions of libpng :

    # revdep-rebuild

References
=========
  [ 1 ] CAN-2004-0421
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-0421

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

     https://security.gentoo.org/glsa/200405-06

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
https://bugs.gentoo.org/.

License
======
Copyright 2004 Gentoo Technologies, Inc; referenced text
belongs to its owner(s).

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

https://creativecommons.org/licenses/by-sa/1.0/

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