More than a week before, from an earlier position that held it would not patch Flash until late October. Instead, the company promised to update the media player "shortly."

Microsoft, not Adobe, is responsible for patching Flash Player in Windows 8 because the company mimicked Google's Chrome by building the software into IE10, the new operating system's browser. Microsoft announced that move in late May, when its top IE executive, Dean Hachamovitch, said, "By updating Flash through Windows Update, like IE, we make security more convenient for customers."

But the Redmond, Wash. developer ran into trouble from the get-go. Although Adobe shipped a pair of security updates in August that patched eight vulnerabilities, Windows 8 RTM, the finished code that began reaching users that same month, lacked those fixes.

One of the eight Flash bugs has been exploited by hackers, perhaps for months. An known for finding and leveraging unpatched vulnerabilities has been among those hijacking Windows PCs with the flaw.

Friday's Flash update will be offered to Windows 8 RTM, and to the final public beta, Windows 8 Release Preview. That sneak peak, which users downloaded free of charge, does not expire until Jan. 31, 2013.