Arch Linux Security Advisory ASA-201511-9
========================================
Severity: High
Date    : 2015-11-17
CVE-ID  : CVE-2015-7981 CVE-2015-8126
Package : libpng
Type    : multiple issues
Remote  : Yes
Link    : https://wiki.archlinux.org/title/CVE

Summary
======
The package libpng before version 1.6.19-1 is vulnerable to
denial-of-service and arbitrary code execution.

Resolution
=========
Upgrade to 1.6.19-1.

# pacman -Syu "libpng>=1.6.19-1"

The problems have been fixed upstream in version 1.6.19.

Workaround
=========
None.

Description
==========
- CVE-2015-7981 (out-of-bounds read)

This is an array indexing error, which can lead to an out-of-bounds read
of a static buffer. The result is now unsigned (no longer negative, but
now a huge positive number).

- CVE-2015-8126 (arbitrary code execution)

Buffer overflow vulnerabilities in functions png_get_PLTE/png_set_PLTE,
allowing remote attackers to cause DoS to application or have
unspecified other impact. These functions failed to check for an
out-of-range palette when reading or writing PNG files with a bit_depth
less than 8. Some applications might read the bit depth from the IHDR
chunk and allocate memory for a 2^N entry palette, while libpng can
return a palette with up to 256 entries even when the bit depth is less
than 8.

Impact
=====
A remote attacker is able to create specially crafted png files that,
when opened or processed, may lead to denial-of-service or possibly
arbitrary code execution.

References
=========
https://access.redhat.com/security/cve/CVE-2015-7981
https://access.redhat.com/security/cve/CVE-2015-8126
https://seclists.org/oss-sec/2015/q4/161
https://seclists.org/oss-sec/2015/q4/264
https://bugs.archlinux.org/task/47069