lwp-download in libwww-perl before 5.835 does not reject downloads to filenames that begin with a . (dot) character, which allows remote servers to create or overwrite files via (1) a 3xx redirect to a URL with a crafted filename or (2) 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.
https://bugzilla.redhat.com/show_bug.cgi?id=602800
https://bugzilla.redhat.com/show_bug.cgi?id=591580
http://www.vupen.com/english/advisories/2010/2872
http://www.ubuntu.com/usn/USN-981-1
http://www.ocert.org/advisories/ocert-2010-001.html
http://marc.info/?l=oss-security&m=127611288927500&w=2
http://marc.info/?l=oss-security&m=127411372529485&w=2
http://lists.fedoraproject.org/pipermail/package-announce/2010-November/050245.html
http://lists.fedoraproject.org/pipermail/package-announce/2010-November/050232.html
http://cpansearch.perl.org/src/GAAS/libwww-perl-5.836/Changes