Mozilla was informed today about the issuance of at least one fraudulent SSL certificate for public websites belonging to Google, Inc. This is not a Firefox-specific issue, and the certificate has now been revoked by its issuer, DigiNotar. This should protect most users.
You can also manually disable the DigiNotar root
through the Firefox preferences.
Instruction for K-Meleon users.
> View Data
> View Certificates
> select Authorities
tab. Scroll down to DigiNotar and select the DigiNotar Root CA, click Delete, then OK to confirm the deletion.