The remote host is missing an update to lftp announced via advisory DSA 2085-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202085-1

It was discovered that in lftp, a command-line HTTP/FTP client, there is no proper validation of the filename provided by the server through the Content-Disposition header attackers can use this flaw by suggesting a filename they wish to overwrite on the client machine, and then possibly execute arbitrary code (for instance if the attacker elects to write a dotfile in a home directory). For the stable distribution (lenny), this problem has been fixed in version 3.7.3-1+lenny1. For the testing distribution (squeeze), this problem has been fixed in version 4.0.6-1. For the unstable distribution (sid), this problem has been fixed in version 4.0.6-1. We recommend that you upgrade your lftp packages.