Facebook failed to warn users of risks from single sign-on tool

Facebook users suing the world’s largest social media network over a 2018 data breach say it failed to warn them about risks tied to its single sign-on tool, even though it protected its employees, a court filing on Thursday showed.

Single sign-on connects users to third-party social apps and services using their Facebook credentials.

The lawsuit, which combined several legal actions, stems from Facebook Inc’s worst-ever security breach in September, when hackers stole login codes – or “access tokens” – that allowed them to access nearly 29 million accounts.