Web performance and security service Cloudflare revealed on Thursday that a coding error has caused information leaks from websites that use Cloudflare.
The company advised users to change their passwords if they use the same password for other websites that may have been affected.
The leak caused some sensitive data to to be cached on search engines such as Google.
The leak may have been active since September 22, but Graham-Cumming stated that the greatest period of impact was February 13-18.