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.

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.

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.

Arbitrary File Upload exists in the Proclaim 9.1.1 component for Joomla! via a mediafileform action.

Backup Download exists in the Proclaim 9.1.1 component for Joomla! via a direct request for a .sql file under backup/.

custom/run.cgi in Webmin before 1.870 allows remote authenticated administrators to conduct XSS attacks via the description field in the custom command functionality.

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.

Webmin before 1.860 has XSS with resultant remote code execution. Under the 'Others/File Manager' menu, there is a 'Download from remote URL' option to download a file from a remote server. After setting up a malicious server, one can wait for a file download request and then send an XSS payload that will lead to Remote Code Execution, as demonstrated by an OS command in the value attribute of a name='cmd' input element.

CSRF exists in Webmin 1.850. By sending a GET request to at/create_job.cgi containing dir=/&cmd= in the URI, an attacker to execute arbitrary commands.

Multiple Cross-site scripting (XSS) vulnerabilities in Webmin before 1.850 allow remote attackers to inject arbitrary web script or HTML via the sec parameter to view_man.cgi, the referers parameter to change_referers.cgi, or the name parameter to save_user.cgi. NOTE: these issues were not fixed in 1.840.