Buffer overflow in qpopper (aka qpop or popper) 4.0 through 4.0.2 allows remote attackers to gain privileges via a long username.
https://exchange.xforce.ibmcloud.com/vulnerabilities/6647
http://www.securityfocus.com/bid/2811
http://www.securityfocus.com/archive/1/188267
http://marc.info/?l=vuln-dev&m=98777649031406&w=2
http://archives.neohapsis.com/archives/linux/caldera/2001-q3/0006.html