Mozilla Firefox is an open source web browser.
A heap-based buffer overflow flaw was found in the way Firefox handled PNG (Portable Network Graphics) images. A web page containing a malicious PNG image could cause Firefox to crash or, possibly, execute arbitrary code with the privileges of the user running Firefox. (CVE-2011-3026)
All Firefox users should upgrade to this updated package, which corrects this issue. After installing the update, Firefox must be restarted for the changes to take effect.