On Friday, the company announced on its blog that it had discovered a technical flaw that would allow application developers using its software to access images that people carried on Facebook but did not share.
The error affected 6.8 million users, 1,500 applications and 876 application developers, the company said, noting that the flaw occurred in September and lasted for 12 days.
The company apologized to users for this error, and promised to put tools for developers next week applications allow them to identify users who have been affected by this error, and delete their images.
Facebook reported that users affected by this incident will receive notices from the company to clarify the bugs and procedures to be followed.
It also advised users to check the applications in which their photos were shared on Facebook to verify the privacy of the images they could access, the statement said.