Race condition in MDaemon 2.8.5.0 POP server allows local users to cause a denial of service by entering a UIDL command and quickly exiting the server.
https://exchange.xforce.ibmcloud.com/vulnerabilities/4745
http://www.securityfocus.com/bid/1366
http://archives.neohapsis.com/archives/ntbugtraq/2000-q2/0277.html