Red Hat Security Advisory 2015-1693-01 – Mozilla Firefox is an open source web browser. XULRunner provides the XUL Runtime environment for Mozilla Firefox. A flaw was 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 installation of add-ons. An attacker could use this flaw to bypass the add-on installation prompt, and trick the user into installing an add-on from a malicious source.