Amazon Linux AMI Security Advisory: ALAS-2012-49
Advisory Release Date: 2014-09-14 15:23 Pacific
A heap-based buffer overflow flaw was found in libpng. An attacker could create a specially-crafted PNG image that, when opened, could cause an application using libpng to crash or, possibly, execute arbitrary code with the privileges of the user running the application. (CVE-2011-3026 )
Run yum update libpng to update your system.