Has your Facebook account been hacked? Attackers stole access tokens to 50 million Facebook accounts. That allowed them to login to accounts and steal user information.
Facebook does not know who is behind the attack or how much information they stole. What can you do about it?
Change your Facebook password and change the password of any other accounts where you may have used the same password. It is a bad practice to use the same password in multiple places. If hackers steal your password from one account, they can hack into your other accounts using your email address and that password.
Use a free service like LastPass to remember and use longer, complicated, more secure passwords. Some people don't like the idea of trusting their passwords to a service like LastPass, but that is a far safer approach to internet safety than using passwords that most people use. You would be surprised at how easy it is to crack the "strong" passwords that most people make up.
Watch out for impostor scams. If the Facebook thieves stole personal information from your account, they could use it to pose as you or as a company that you do business with, contacting you with a convincing scam.
Keep tabs on your financial accounts. The thieves might try to impersonate you to change your account passwords and steal from you.
Be careful out there!