According to a report from Motherboard, an Uber driver spotted the bug while uploading a document on Tuesday to the driver web portal. The site loaded hundreds of other drivers’ documents and information including drivers license scans, Social Security numbers and tax forms. The driver, who remains anonymous, reported the bug to Uber, which told Motherboard it fixed within 30 minutes of being alerted of it.

“We were notified about a bug impacting a fraction of our U.S. drivers earlier this afternoon,“ an Uber spokesperson told Motherboard. “We’d like to thank the driver who drew it to our attention and apologize to those drivers whose information may have been affected. Their security is incredibly important to Uber and we will follow up with them directly.”

Uber said the leak affected 674 drivers in the U.S.

This isn’t the first time Uber data has been exposed. As Motherboard notes, Uber recently fixed a security issue that let hackers maintain control of compromised accounts even after the passenger changed their passwords. Uber has also filed a lawsuit related to a data breach in 2014 that exposed more than 50,000 drivers’ information.