Mozilla has been informed about the issuance of several fraudulent SSL certificates for public websites. The certificates have been revoked by their issuer which should protect most users. This is not a Firefox-specific issue. As part of our ongoing commitment to providing a secure Web experience for users, we have updated Firefox 4.0, 3.6, and 3.5 to recognize these certificates and block them automatically.
Current versions of Firefox are protected from this attack. We are still evaluating the possibility of further response to this issue. We encourage all users to keep their software up to date by regularly applying security updates.