The libpng packages contain a library of functions for creating and manipulating PNG image format files. A buffer overflow flaw was found in the way libpng processed certain PNG image files. An attacker could create a specially-crafted PNG image that, when opened, could cause an application using libpng to crash or, potentially, execute arbitrary code with the privileges of the user running the application. Note: The application behavior required to exploit CVE-2011-2690 is rarely used. No application shipped with Red Hat Enterprise Linux behaves this way, for example. An uninitialized memory read issue was found in the way libpng processed certain PNG images that use the Physical Scale extension. An attacker could create a specially-crafted PNG image that, when opened, could cause an application using libpng to crash. Users of libpng should upgrade to these updated packages, which contain backported patches to correct these issues. All running applications using libpng must be restarted for the update to take effect.