The update went live at 10 a.m. Pacific time Thursday.
Adrienne Hall, general manager of Microsoft Trustworthy Computing, said the company decided to fix the problem quickly for all customers, saying it takes the security of its products “incredibly seriously.”
Microsoft reported the problem Saturday, saying it was aware of “limited, targeted attacks” and that the vulnerability affected Internet Explorer versions 6 through 11
The company said users with automatic updates enabled don't need to take any action.
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