Mozilla Firefox is an open source web browser. XULRunner provides the XULRuntime environment for Mozilla Firefox.It was found that a Certificate Authority (CA) issued a fraudulent HTTPScertificate. This update renders any HTTPS certificates signed by thatCA as untrusted, except for a select few. The now untrusted certificatesthat were issued before July 1, 2011 can be manually re-enabled and usedagain at your own risk in Firefox; however, affected certificates issuedafter this date cannot be re-enabled or used. (BZ#734316)All Firefox users should upgrade to these updated packages, which containa backported patch. After installing the update, Firefox must be restartedfor the changes to take effect.