Over 500 million Facebook users had their personal data posted online on Saturday, the Business Insider reported.
The information, which was available for free, includes phone numbers, Facebook IDs, locations, full names, birthdays, bios, and sometimes email addresses, for 533 million Facebook users, the Business Insider added.
The leak was discovered by Hudson Rock's chief technology officer, Alon Gal, the site said.
The Insider verified several of the records by matching the known phone numbers with the IDs listed, and confirmed others by testing email addresses from data in the password reset feature.
"Individuals signing up to a reputable company like Facebook are trusting them with their data," Gal told the Insider, emphasizing that "Facebook [is] supposed to treat the data with utmost respect" and that such leaks are "a huge breach of trust and should be handled accordingly."
Facebook did not immediately respond to an email seeking comment on Saturday, Bloomberg noted.