(1) Webmin 0.96 and (2) Usermin 0.90 with password timeouts enabled allow local and possibly remote attackers to bypass authentication and gain privileges via certain control characters in the authentication information, which can force Webmin or Usermin to accept arbitrary username/session ID combinations.
Directory traversal vulnerability in edit_action.cgi of Webmin Directory 0.91 allows attackers to gain privileges via a '..' (dot dot) in the argument.