The remote host is missing an update as announced via advisory SSA:2005-203-05.

https://secure1.securityspace.com/smysecure/catid.html?in=SSA:2005-203-05

New fetchmail packages are available for Slackware 8.1, 9.0, 9.1, 10.0, 10.1, and -current to fix security issues. Connecting to a malicious or compromised POP3 server may overflow fetchmail's stack causing a crash or the execution of arbitrary code. For more information about this issue, see: http://fetchmail.berlios.de/fetchmail-SA-2005-01.txt