Chartbrew is an open-source web application that can connect directly to databases and APIs and use the data to create charts. In version 4.9.0, the endpoint POST /user/invited does not validate any invite token, authentication header, or session. Any unauthenticated attacker can call this endpoint directly to create a fully active account and receive a valid JWT — even when the instance has existing users and signupRestricted is enabled. This bypass is distinct from the normal registration endpoint (POST /user) which enforces signupRestricted and sets active: false pending verification. This issue has been patched in version 5.0.0.