From the BBC News:

Users of Microsoft's Internet Explorer are being urged by experts to switch to a rival until a serious security flaw has been fixed. The flaw in Microsoft's Internet Explorer could allow criminals to take control of people's computers and steal their passwords, internet experts say....
      "Microsoft is continuing its investigation of public reports of attacks against a new vulnerability in Internet Explorer," said the firm in a security advisory alert about the flaw.
      Microsoft says it has detected attacks against IE 7.0 but said the "underlying vulnerability" was present in all versions of the browser. Other browsers, such as Firefox, Opera, Chrome, Safari, are not vulnerable to the flaw Microsoft has identified.