Authorizer is an open-source, self-hostable authentication and authorization server. Prior to version 2.2.1, the /authorize endpoint accepts any redirect_uri without validating it against AllowedOrigins. When response_type=token or response_type=id_token, the server appends access_token, id_token, and refresh_token as query parameters and issues a 302 redirect to the attacker-supplied URL. An unauthenticated attacker can obtain the required client_id from the public /graphql?query={meta{client_id}} endpoint. A partial fix was applied in v2.0.1 to other handlers (oauth_login, verify_email, magic_link_login, forgot_password, invite_members, oauth_callback) but /authorize was not included. Version 2.2.1 contains a more complete fix.