Multiple vulnerabilities in libpng might allow remote attackers to
execute arbitrary code or cause a Denial of Service condition.
Background
libpng is a standard library used to process PNG (Portable Network
Graphics) images. It is used by several programs, including web browsers
and potentially server processes.
Multiple vulnerabilities have been discovered in libpng:
The “embedded_profile_len()” function in pngwutil.c does not
check for negative values, resulting in a memory leak (CVE-2009-5063).
The “png_format_buffer()” function in pngerror.c contains an
off-by-one error (CVE-2011-2501).
The “png_rgb_to_gray()” function in pngrtran.c contains an
integer overflow error (CVE-2011-2690).
The “png_err()” function in pngerror.c contains a NULL pointer
dereference error (CVE-2011-2691).
The “png_handle_sCAL()” function in pngrutil.c improperly handles
malformed sCAL chunks(CVE-2011-2692).
The “png_decompress_chunk()” function in pngrutil.c contains an
integer overflow error (CVE-2011-3026).
The “png_inflate()” function in pngrutil.c contains and out of
bounds error (CVE-2011-3045).
The “png_set_text_2()” function in pngset.c contains an error
which could result in memory corruption (CVE-2011-3048).
The “png_formatted_warning()” function in pngerror.c contains an
off-by-one error (CVE-2011-3464).
Impact
An attacker could exploit these vulnerabilities to execute arbitrary
code with the permissions of the user running the vulnerable program,
which could be the root user, or to cause programs linked against the
library to crash.
Workaround
There is no known workaround at this time.
Resolution
All libpng 1.5 users should upgrade to the latest version:
Security is a primary focus of Gentoo Linux and ensuring the confidentiality and security of our users machines is of utmost importance to us. Any security concerns should be addressed to security@gentoo.org or alternatively, you may file a bug at https://bugs.gentoo.org.