Thousands of Uber driver names and driver's license numbers may be in the hands of an unauthorized third party due to a data breach that occurred last year, the ride-hailing company said Friday. lRelated 13.5 million Californians affected by Anthem data breach. In a statement, Uber's managing counsel of data privacy, Katherine Tassi, said the company discovered on Sept. 17, 2014, that one of its many databases could have potentially been accessed because one of the encryption keys required to unlock it had been compromised. Upon further investigation, it found the database had been accessed once by an unauthorized third party on May 13, 2014. The company said it could not say how the security vulnerability was first discovered because the matter was under investigation. According to Tassi, the company immediately patched the security vulnerability. It has not received any reports of misuse of the data. The database contained only the names and license numbers of approximately 50,000 former and current Uber drivers from various states, the company said. Of the affected drivers, approximately 21,000 are based in California, it said.