You don't say what you mean "that stores the data". What data? Any login system will of course store user identity info. Do you also want a system that will store additional data in each user's profile (rather than storing it in your own database)?
) has this feature (they call this "attributes") as well as the ability to support logging in with just an email address or through Facebook, Twitter, Google, GitHub, Windows Live, Linked In, etc. They also support the ability to login with only client-side code if you want that.
EDIT: I wouldn't recommend using a CMS just for the login functionality. That's using a sledgehammer when you need a screwdriver. That said, if you are using a CMS then you should definitely consider using built-in or built-for login solutions. You didn't provide any information about what you're building so all our answers have a bit of speculation in them.