SSRF exists in Webmin 1.850 via the PATH_INFO to tunnel/link.cgi, as demonstrated by a GET request for tunnel/link.cgi/http://INTRANET-IP:8000.
https://github.com/webmin/webmin/commit/0c58892732ee7610a7abba5507614366d382c9c9
https://euvd.enisa.europa.eu/vulnerability/EUVD-2017-7095
https://blogs.securiteam.com/index.php/archives/3430