Not good, Google:

Google Inc. has quietly patched a potentially dangerous security flaw in two of its business-facing services after a private security research outfit warned that malicious hackers could exploit the bug to hijack sensitive user information.

The vulnerability was flagged—and fixed—in the Google AdWords and Google Services subdomains.

Because both sites use data from the Google Accounts username/password system, security experts said the flaw presented a major identity theft risk.

As if click fraud wasn't a bad enough issue. As they continue to collect and cross reference information they need to be careful with that user privacy issue.