YesWiki before 4.6.7 contains a server-side request forgery vulnerability in WebfingerService that allows unauthenticated attackers to trigger HTTPS requests to internal hosts. Attackers can POST a crafted actor_handle with a numeric host and port to the abonnements view to probe internal HTTPS services and ports.
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.