YesWiki before 4.6.7 contains an unauthenticated server-side request forgery vulnerability that allows remote attackers to make the server fetch arbitrary URLs by supplying a syndication action through the render handlers content parameter. Attackers can target internal hosts and ports, read back fetched feed content in the rendered page, and cause feed enclosures to be downloaded into the files directory.
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.