stylistic:tone
Breaches

On September 28, 2018, Facebook experienced a major breach in its security, exposing the data of 50 million users. The data breach started in July 2017 and was discovered on September 16. Facebook notified users affected by the exploit and logged them out of their accounts.

In March 2019, Facebook confirmed a password compromise of millions of Facebook lite application users also affected millions of Instagram users. The reason cited was the storage of password as plain text instead of encryption which could be read by its employees.

On December 19, 2019, security researcher Bob Diachenko discovered a database containing more than 267 million Facebook user IDs, phone numbers, and names that were left exposed on the web for anyone to access without a password or any other authentication.

In February 2020, Facebook encountered a major security breach in which its official Twitter account was hacked by a Saudi Arabia -based group called " OurMine ". The group has a history of actively exposing high-profile social media profiles' vulnerabilities.

In April 2021, The Guardian reported approximately half a billion users' data had been stolen including birthdates and phone numbers. Facebook alleged it was "old data" from a problem fixed in August 2019 despite the data's having been released a year and a half later only in 2021; it declined to speak with journalists, had apparently not notified regulators, called the problem "unfixable", and said it would not be advising users.