Microsoft began investigating this flaw earlier in March, but now that hackers have begun exploiting it, the company decided to issue a patch immediately rather than wait for its regularly schedule monthly security patch release. The next such release is set for next week, and will include nine unrelated updates. (Some of which also apply to IE 8.) Given the timing of the next scheduled update, the danger level must be high for Microsoft to deliver an out-of-band update just days earlier.