The MITRE CVE dictionary describes this issue as:
The get1 command, as used by lftpget, in LFTP before 4.0.6 does not properly validate a server-provided filename before determining the destination filename of a download, which allows remote servers to create or overwrite arbitrary files via a Content-Disposition header that suggests a crafted filename, and possibly execute arbitrary code as a consequence of writing to a dotfile in a home directory.
Find out more about CVE-2010-2251 from the
MITRE CVE dictionary dictionary and
This issue did not affect the version of lftp as shipped with Red Hat Enterprise Linux 3 and 4 as they did not include support for renaming files to a server-suggested file name.