Mozilla Firefox is an open source web browser. 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 malformed JavaScript. A website with an object containing malicious JavaScript could cause Firefox to execute that JavaScript with the privileges of the user running Firefox. This update adds support for the Sanitiser for OpenType library to Firefox. This library helps prevent potential exploits in malformed OpenType fonts by verifying the font file prior to use. A flaw was found in the way Firefox loaded Java LiveConnect scripts. Malicious web content could load a Java LiveConnect script in a way that would result in the plug-in object having elevated privileges, allowing it to execute Java code with the privileges of the user running Firefox. It was found that the fix for CVE-2010-0179 was incomplete when the Firebug add-on was used. If a user visited a website containing malicious JavaScript while the Firebug add-on was enabled, it could cause Firefox to execute arbitrary JavaScript with the privileges of the user running Firefox. A flaw was found in the way Firefox presented the location bar to users. A malicious website could trick a user into thinking they are visiting the site reported by the location bar, when the page is actually content controlled by an attacker. A cross-site scripting flaw was found in the Firefox x-mac-arabic, x-mac-farsi, and x-mac-hebrew character encodings. Certain characters were converted to angle brackets when displayed. If server-side script filtering missed these cases, it could result in Firefox executing JavaScript code with the permissions of a different website. For technical details regarding these flaws, refer to the Mozilla security advisories for Firefox 3.6.13. 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 3.6.13, which corrects these issues. After installing the update, Firefox must be restarted for the changes to take effect.