A data firm working for Republican clients, including the Republican National Committee, left databases containing the personal information of more than 198 million voters exposed on an unsecure Amazon cloud server, a cyber company discovered.

Chris Vickery, a cyber risk analyst for UpGuard, came across the data, which includes the names, birth dates, home addresses, phone numbers and voter registration information belonging to nearly all 200 million people registered to vote in the U.S.