png -- libpng decompression buffer overflow

The PNG project describes the problem in an advisory:

Several versions of libpng through 1.4.2 (and through 1.2.43
in the older series) contain a bug whereby progressive
applications such as web browsers (or the rpng2 demo app included
in libpng) could receive an extra row of image data beyond the
height reported in the header, potentially leading to an
out-of-bounds write to memory (depending on how the application
is written) and the possibility of execution of an attacker’s
code with the privileges of the libpng user (including remote
compromise in the case of a libpng-based browser visiting a
hostile web site).