We recently received a report to our White Hat program regarding a bug that may have allowed some of a person’s contact information (email or phone number) to be accessed by people who either had some contact information about that person or some connection to them.
We've concluded that approximately 6 million Facebook users had email addresses or telephone numbers shared. There were other email addresses or telephone numbers included in the downloads, but they were not connected to any Facebook users or even names of individuals. For almost all of the email addresses or telephone numbers impacted, each individual email address or telephone number was only included in a download once or twice. This means, in almost all cases, an email address or telephone number was only exposed to one person. Additionally, no other types of personal or financial information were included and only people on Facebook – not developers or advertisers – have access to the DYI tool.