libpng: Buffer overflow on row buffers — GLSA 200407-06

libpng contains a buffer overflow vulnerability potentially allowing an attacker to perform a Denial of Service attack or even execute arbitrary code.

Affected packages

Package 	media-libs/libpng on all architectures
Affected versions 	<= 1.2.5-r6
Unaffected versions 	>= 1.2.5-r7

Background

libpng is a standard library used to process PNG (Portable Network Graphics) images. It is used by several other programs, including web browsers and potentially server processes.

Description

Due to a wrong calculation of loop offset values, libpng contains a buffer overflow vulnerability on the row buffers. This vulnerability was initially patched in January 2003 but since it has been discovered that libpng contains the same vulnerability in two other places.

Impact

An attacker could exploit this vulnerability to cause programs linked against the library to crash or execute arbitrary code with the permissions of the user running the vulnerable program, which could be the root user.

Workaround

There is no known workaround at this time. All users are encouraged to upgrade to the latest available version.

Resolution

All libpng users should upgrade to the latest stable version:

 # emerge sync

 # emerge -pv ">=media-libs/libpng-1.2.5-r7"
 # emerge ">=media-libs/libpng-1.2.5-r7"

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

 # revdep-rebuild

References

    CAN-2002-1363