Nearly 5 million Gmail usernames and passwords surfaced on Wednesday on a Russian Bitcoin forum.
According to The Daily Dot, much of the information is old or out-of-date. Many of the accounts are suspended or have been matched to old passwords. The leak appears to have been collected via phishing and hacking over several years.
In a statement, Google said, "The security of our users' information is a top priority for us. We have no evidence that our systems have been compromised, but whenever we become aware that accounts may have been, we take steps to help those users secure their accounts."
Users are urged to change their passwords often and enable two-step verification to their accounts.
—By CNBC Staff