Adobe is adding a sandbox to the version of the player that runs in Firefox. The sandbox is designed to prevent many common exploit techniques against Flash. Adobe officials have said that the introduction of the sandbox in Adobe Reader X, known as Protected Mode, was one of the more important security advances for protecting the company s users. The version of Flash for Firefox that includes a sandbox is now in beta form, and is only available to developers and not end users, Adobe said. The final version should be available for users later this year.
Source: https://threatpost.com/flash-sandbox-works-firefox-020612/76179/