Mozilla Firefox is an open source Web browser. XULRunner provides the XUL Runtime environment for Mozilla Firefox. Several use-after-free flaws were found in Firefox. Visiting a web page containing malicious content could result in Firefox executing arbitrary code with the privileges of the user running Firefox. A flaw was found in Firefox that could allow an applet to generate a drag and drop action from a mouse click. Such an action could be used to execute arbitrary JavaScript with the privileges of the user running Firefox. A privilege escalation flaw was found in Firefox when the Firebug add-on is in use. The XMLHttpRequestSpy module in the Firebug add-on exposes a Chrome privilege escalation flaw that could be used to execute arbitrary JavaScript with the privileges of the user running 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. For technical details regarding these flaws, refer to the Mozilla security advisories for Firefox 3.0.19. 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 3.0.19, which corrects these issues. After installing the update, Firefox must be restarted for the changes to take effect.