Zitadel before 4.16.2 contains a server-side request forgery vulnerability that allows attackers to make the server request internal resources through organization domain HTTP verification. The challenge fetch uses Gos default http.Get instead of the protected client, so attackers can register domains that redirect to loopback, internal, or cloud metadata addresses to scan ports and map internal networks.
Weakness
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.