Millions of Facebook users had posts they marked private made public so that anyone could see them, the company said.
The social media company said on Thursday that the posts were made between May 18 and May 27.
The exposure of the private posts happened while a new feature was being tested, reported Fox 46.
Users can select different levels of privacy on their Facebook accounts, but even some users who selected the strictest settings saw posts made public.
Facebook said that around 14 million people had their private posts changed to public.
Users responded to the news with some saying that there’s no reasonable expectation of much privacy on Facebook, while others said that the news was startling.
Facebook claims that users who were affected have had all their posts changed back to private. Such users should have received a notification on Thursday asking them to review their posts.