The libpng packages contain a library of functions for creating and manipulating PNG (Portable Network Graphics) image format files.
A heap-based buffer overflow flaw was found in the way libpng processed tEXt chunks in PNG image files. An attacker could create a specially-crafted PNG image file 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-2011-3048)
Users of libpng should upgrade to these updated packages, which correct this issue. For Red Hat Enterprise Linux 5, they contain a backported patch. For Red Hat Enterprise Linux 6, they upgrade libpng to version 1.2.49. All running applications using libpng must be restarted for the update to take effect.