libpng denial of service vulnerability — GLSA 200405-06

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

Affected packages

Package 	media-libs/libpng on all architectures
Affected versions 	<= 1.2.5-r4
Unaffected versions 	>= 1.2.5-r5

Background

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

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

    CAN-2004-0421