An unknown attacker was able to infiltrate the CA infrastructure at DigiNotar, a Dutch company that sells commercial SSL certificates. The attack came to light earlier this week when users in Iran noticed some odd re-routing of traffic going to and from Gmail. The compromise of a trusted root CA, albeit a relatively small one, has wide-ranging ramifications. Users going to one of the sites will see an error message warning them about the invalid certificate. Update your browser to take advantage of the patches that disable the certificate. You can download the newest version of Chrome from Google.
Source: https://threatpost.com/what-you-need-know-about-diginotar-hack-090211/75611/