Webmin is a web-based system administration tool for Unix-like servers. Prior to 2.652, untrusted users with access to the File Manager or Upload and Download modules can direct Webmin's server-side URL download functionality to non-public network addresses because download destinations are not restricted by resolved IP address. This allows requests to unauthenticated intranet services or cloud-provider instance metadata endpoints that are inaccessible from the user's own system. This issue is fixed in 2.652.
Server-Side Request Forgery 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.