In December 2018, Quora announced that approximately 100 million user accounts were affected by a
data breach.
[37][40] The hacked information included users' names, email addresses, encrypted passwords, data from social networks like
Facebook and
Twitter if people had chosen to link them to their Quora accounts, questions they had asked, and answers they had written.
[40] Adam D'Angelo stated, "The overwhelming majority of the content accessed was already public on Quora, but the compromise of account and other private information is serious."
[40] Compromised information could also allow hackers to log into a Quora user's connected social media accounts, via access tokens. A class action lawsuit, case number 5:18-cv-07597-BLF, was filed in the Northern District of California, on behalf of named plaintiffs in New Jersey and Colorado.
[41][42]