You may have woken up to being unable to login into your Yahoo Account today and wondered what was happening.
Well, according to Yahoo, data from at least 500 million Yahoo users was "stolen" during an attack in 2014.
The internet company has said that the attack may have been "state-sponsored". However, an investigation has found no evidence that the state-sponsored actor is currently in Yahoo's network.
Yahoo said the stolen data may have included names, dates of birth, and hashed passwords but may not have included unprotected passwords, payment card data or bank account information.
Alex Holden who was interviewed by the New York Times said the attack is "one of the biggest breaches of people's privacy and very far reaching".
The founder of Hold Security, which has been tracking the flow of stolen Yahoo credentials on the underground web added that the stolen Yahoo data is critical because it leads to users' connections to their banks, other financial services, social media profiles and users' family and friends.
Potentially affected users have been notified, asked to change their passwords and use other ways of verifying their accounts.