libpng - buffer overflow

Developers of the PNG library have fixed a buffer overflow in the
progressive reader when the PNG datastream contains more IDAT data
than indicated by the IHDR chunk. Such deliberately malformed
datastreams would crash applications which could potentially allow an
attacker to execute malicious code. Programs such as Galeon,
Konqueror and various others make use of these libraries.

In addition to that, the packages below fix another
potential buffer overflow. The PNG libraries implement a safety
margin which is also included in a newer upstream release. Thanks to
Glenn Randers-Pehrson for informing us.

To find out which packages depend on this library, you may want to
execute the following commands:

    apt-cache showpkg libpng2
    apt-cache showpkg libpng3

This problem has been fixed in version 1.0.12-3.woody.2 of libpng and
version 1.2.1-1.1.woody.2 of libpng3 for the current stable
distribution (woody) and in version 1.0.12-4 of libpng and version
1.2.1-2 of libpng3 for the unstable distribution (sid).
The potato release of Debian does not seem to be vulnerable.

We recommend that you upgrade your libpng packages immediately and
restart programs and daemons that link to these libraries and read
external data, such as web browsers.