A controversial company that was recently criticized for compiling billions of images downloaded from Facebook, YouTube, and Venmo said its entire client list was stolen during a security failure.

Clearview AI, a facial-recognition startup that has faced scrutiny from privacy advocates, notified customers on Wednesday that an intruder “gained unauthorized access” to its list of customers and private data associated with the number of accounts set up by users and searches within the Clearview database. The company told users the intruder was unable to compromise Clearview’s systems or network.