FTP Explorer 1.0.1 Build 047, and other versions before 1.0.1.52, allows remote servers to cause a denial of service (CPU consumption) via a long response to a PWD command.
https://www.exploit-db.com/exploits/3347
https://exchange.xforce.ibmcloud.com/vulnerabilities/32606
http://www.attrition.org/pipermail/vim/2007-March/001470.html