The details of 100 million Facebook users have been copied, compiled into a single downloadable file and leaked onto the Internet.
Ron Bowes, an online security consultant, used a custom made code to scan and copy the 500 million Facebook profiles for information not hidden by Facebook's new privacy settings.
The resulting file has already been downloaded by thousands of people via torrent clients.
On his website, www.skullsecurity.org, Bowes said he was able to capture details of 100 million unique profiles.
"As I thought more about it and talked to other people, I realized that this is a scary privacy issue. I can find the name of pretty much every person on Facebook," he wrote.
"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," Bowes continued.
Facebook downplayed the issue, saying that no private data had been compromised.
"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," Facebook said via a statement to msnbc.com.
"Our responsibility is to respect their wishes. In this case, information that people have agreed to make public was collected by a single researcher. This information already exists in Google, Bing, other search engines, as well as on Facebook," it added.
"No private data is available or has been compromised. Similar to a phone book, this is the information available to enable people to find each other, which is the reason people join Facebook. If someone does not want to be found, we also offer a number of controls to enable people not to appear in search on Facebook, in search engines, or share any information with applications."
It comes at the heel of Facebook celebrating its 500 million active profiles milestone last week.
Facebook chief executive Mark Zuckerberg. The company is downplaying the newest leak of individuals' information. (April 2010)