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                                   CERT-Renater

                        Note d'Information No. 2010/VULN077
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DATE                      : 09/03/2010

HARDWARE PLATFORM(S)      : /

OPERATING SYSTEM(S)       : Systems running libpng versions prior to
                               1.4.1, 1.2.43, 1.0.53.

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http://libpng.sourceforge.net/ADVISORY-1.4.1.html
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PNG Reference Library: libpng
	PNG Web Site
Security Advisory for libpng-1.4.0 and earlier, 27 February 2010

Because of the efficient compression method used in Portable Network
Graphics (PNG) files, a small PNG file can expand tremendously, acting
as a "decompression bomb". Malformed PNG chunks can consume a large
amount of CPU and wall-clock time and large amounts of memory, up to
all memory available on a system.

Eventually libpng would discover that the chunk was malformed or
would run out of memory, abandon the chunk and return the allocated
memory, so this is only a nasty Denial of Service (DoS) vulnerability
that probably cannot be used to compromise a system.

Libpng versions 1.4.1, 1.2.43, and 1.0.53 have been revised to use
less CPU time and memory. Libpng-1.4.1 also provides functions that
applications can use to further defend against such files.

For further details, see the libpng document "Defending Libpng
pplications Against Decompression Bombs", available at
<http://libpng.sourceforge.net/decompression_bombs.html>

The PNG Development Group recommends that everyone upgrade to
libpng version 1.4.1, if at all possible.
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