So this is kind of an odd scenario, but bare with me. My client has been issued a JWT token. After having received and stored it, I completely reset the database, and so also emptied the users table. Note that we're using MySQL with auto incrementing ID, whose counter has been reset. The user ID is stored in the JWT, so now the JWT isn't referencing an existing user anymore, so the client will get a 401. The problem arises when a new user registers and is inserted in the new database. That user will get ID 1, and so the old token for the other user will suddenly be valid for another user. I know it's an odd case, but is this a flaw in JWT? I guess an easy solution would be to use random ID's, but I'm still wondering.