Mozilla Firefox is an open source web browser. XULRunner provides the XUL Runtime environment for Mozilla Firefox. Several flaws were found in the processing of malformed web content. A web page containing malicious content could cause Firefox to crash or, potentially, execute arbitrary code with the privileges of the user running Firefox. A flaw was found in the way Firefox handled certain DOM JavaScript objects. An attacker could use this flaw to make JavaScript client or add-on code make incorrect, security sensitive decisions. Red Hat would like to thank the Mozilla project for reporting these issues. Upstream acknowledges Andre Bargull, Scoobidiver, Bobby Holley, Reuben Morais, Abhishek Arya, Ms2ger, Sachin Shinde, Aki Helin, Nils, and Boris Zbarsky as the original reporters of these issues. For technical details regarding these flaws, refer to the Mozilla security advisories for Firefox 17.0.9 ESR. You can find a link to the Mozilla advisories in the References section of this erratum. All Firefox users should upgrade to these updated packages, which contain Firefox version 17.0.9 ESR, which corrects these issues. After installing the update, Firefox must be restarted for the changes to take effect.