The big security news in Flash player 11.3 is the addition of the protected mode sandbox for Firefox on Windows. That's a major change for Adobe, which has been adding sandbox to its main product lines for a couple of years now. Adobe Reader X has run in protected mode--which is what Adobe calls its sandbox--since its release, and the company also added a sandbox to Flash on Google Chrome. The sandbox is designed to prevent attackers from using vulnerabilities in Flash to break out of the application and move to other apps or the OS itself."
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