Details from 100 million Facebook profiles have been made available on the web by a security consultant.
Canadian security expert Ron Bowes used a piece of code that trawled the social network to capture any details that had not been made private in a bid to highlight privacy issues.
Names, unique IDs and the URLs of every Facebook profile that's been made searchable on the web are among the data that's been collected. However, the list doesn't contain email addresses or telephone numbers.
"This is a scary privacy issue. I can find the name of pretty much every person on Facebook. Once I have the name and URL of a user, I can view, by default, their picture, friends, information about them, and some other details," said Bowes.
"If the user has set their privacy higher, at the very least I can view their name and picture. So, if any searchable user has friends that are non-searchable, those friends just opted into being searched, like it or not.'
However, Facebook said all of the information was already publicly available.
"People who use Facebook own their information and have the right to share only what they want, with whom they want, and when they want," the social network told the BBC.
"In this case, information that people have agreed to make public was collected by a single researcher and already exists in Google, Bing, other search engines, as well as on Facebook.
The data was made available on file-sharing site The Pirate Bay and has been downloaded more than 1,000 times.