The unity-firefox-extension package could be tricked into dropping a C callback which was still in use, which Firefox would then free, causing Firefox to crash. This could be achieved by adding an action to the launcher and updating it with new callbacks until the libunity-webapps rate limit was hit. Fixed in 3.0.0+14.04.20140416-0ubuntu1.14.04.1 of unity-firefox-extension and in all versions of libunity-webapps by shipping an empty unity-firefox-extension package, thus disabling the extension entirely and invalidating the attack against the libunity-webapps package.

The unity-firefox-extension package could be tricked into destroying the Unity webapps context, causing Firefox to crash. This could be achieved by spinning the event loop inside the webapps initialization callback. Fixed in 3.0.0+14.04.20140416-0ubuntu1.14.04.1 by shipping an empty package, thus disabling the extension entirely.

content/unity-api.js in the unity-firefox-extension extension 2.4.1 for Firefox exposes the toDataURL function in an API call, which allows remote attackers to bypass the Same Origin Policy and obtain sensitive information via a crafted webpage.

Unity integration extension (unity-firefox-extension) before 2.4.1 for Firefox does not properly handle callbacks, which allows remote attackers to cause a denial of service (Firefox crash) and possibly execute arbitrary code via a crafted request.