Webmin 1.900 allows remote attackers to execute arbitrary code by leveraging the "Java file manager" and "Upload and Download" privileges to upload a crafted .cgi file via the /updown/upload.cgi URI.

rpc.cgi in Webmin through 1.920 allows authenticated Remote Code Execution via a crafted object name because unserialise_variable makes an eval call. NOTE: the Webmin_Servers_Index documentation states "RPC can be used to run any command or modify any file on a server, which is why access to it must not be granted to un-trusted Webmin users."

xmlrpc.cgi in Webmin through 1.930 allows authenticated XXE attacks. By default, only root, admin, and sysadm can access xmlrpc.cgi.

In Webmin through 1.910, any user authorized to the "Package Updates" module can execute arbitrary commands with root privileges via the data parameter to update.cgi.

An issue was discovered in Webmin 1.840 and 1.880 when the default Yes setting of "Can view any file as a log file" is enabled. As a result of weak default configuration settings, limited users have full access rights to the underlying Unix system files, allowing the user to read sensitive data from the local system (using Local File Include) such as the '/etc/shadow' file via a "GET /syslog/save_log.cgi?view=1&file=/etc/shadow" request.

Webmin 1.890 has XSS via /config.cgi?webmin, the /shell/index.cgi history parameter, /shell/index.cgi?stripped=1, or the /webminlog/search.cgi uall or mall parameter.

Webmin before 2.202 and Virtualmin before 7.20.2 allow a network traffic loop via spoofed UDP packets on port 10000.