Ubuntu Security Notice 2743-3 – USN-2743-1 fixed vulnerabilities in Firefox. Future Firefox updates will require all addons be signed and unity-firefox-extension, webapps-greasemonkey and webaccounts-browser-extension will not go through the signing process. Because these addons currently break search engine installations (LP: #1069793), this update permanently disables the addons by removing them from the system. We apologize for any inconvenience. Various other issues were also addressed.