Microsoft has said it will patch the hole in Internet Explorer that allowed hackers to access a number of email accounts.
A patch is not due until February, but the publicity surrounding the web attacks has forced the software giant to act quicker, BBC News reports.
The recent attacks by Chinese hackers primarily targeted human rights activist, but were also thought to have affected over 30 companies including Google and Adobe.
Microsoft's general manager of its trustworthy computing security group George Stathakopoulos said in a security advisory attended by the BBC: "Given the significant level of attention this issue has generated, confusion about what customers can do to protect themselves and the escalating threat environment Microsoft will release a security update out-of-band for this vulnerability."
He added that that the only successful attacks had been against Internet Explorer 6 and that customers should update to 8 in order to received improved protection.