TokenBasedRememberMeServices assumes user exists when it could not for various reasons:
- The user could have been deleted (Most likely)
- The cookie could be invalid
https://github.com/spring-projects/spring-security/blob/master/web/src/main/java/org/springframework/security/web/authentication/rememberme/TokenBasedRememberMeServices.java#L123-L124
There is no check and such an exception is not handled gracefully.
At the very least, it should throw a InvalidCookieException