Webmin 0.84 and earlier does not properly clear the HTTP_AUTHORIZATION environment variable when the web server is restarted, which makes authentication information available to all CGI programs and allows local users to gain privileges.
https://exchange.xforce.ibmcloud.com/vulnerabilities/6627
http://www.linux-mandrake.com/en/security/2001/MDKSA-2001-059.php3
http://www.calderasystems.com/support/security/advisories/CSSA-2001-019.1.txt
http://archives.neohapsis.com/archives/bugtraq/2001-05/0262.html