CVE-2022-31027

OAuthenticator is an OAuth token library for the JupyerHub login handler. CILogonOAuthenticator is provided by the OAuthenticator package, and lets users log in to a JupyterHub via CILogon. This is primarily used to restrict a JupyterHub only to users of a given institute. The allowed_idps configuration trait of CILogonOAuthenticator is documented to be a list of domains that indicate the institutions whose users are authorized to access this JupyterHub. This authorization is validated by ensuring that the email field provided to us by CILogon has a domain that matches one of the domains listed in allowed_idps.If allowed_idps contains berkeley.edu, you might expect only users with valid current credentials provided by University of California, Berkeley to be able to access the JupyterHub. However, CILogonOAuthenticator does not verify which provider is used by the user to login, only the email address provided. So a user can login with a GitHub account that has email set to