Facebook has said a software bug may have made as many asÂ 14 millionÂ users private content public over several days in May.
The problem, which Facebook says it has fixed, is the latest privacy scandal for the world's largest social media company.
The company said on Thursday that the bug automatically suggested that users make new posts public, even if they had previously restricted to "friends only" or another private setting.
Did not affect past posts
Erin Egan, Facebook's chief privacy officer, says the bug did not affect past posts.
"We recently found a bug that automatically suggested posting publicly when some people were creating their Facebook posts,' said Egan.
"We have fixed this issue and starting today we are letting everyone affected know and asking them to review any posts they made during that time.
When users shared posts on Facebook it was automatically set to public (Photo: Shutterstock)
"To be clear, this bug did not impact anything people had posted before - and they could still choose their audience just as they always have. We'd like to apologise for this mistake."
According to a spokesperson the bug was active from May 18 to May 22, but it took Facebook until May 27 to correct the error.
Facebook believes that around 14 millions were affected by the mistake and has begun contacting them explaining the situation. When users post now Facebook claim that their post will not be automatically set to go public.
The latest blunder
This failure to protect user's privacy is the latest in a long line of blunders by the Silicon Valley behemoth.
On March 17 it was revealed that 50 million users' profiles had been harvested by political consulting firm Cambridge Analytica.
Only days ago Facebook were found to be sharing user data with device makers, including China's Huawei. The deal allowed companies access to users' information including religion and political leaning.