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.

• http://vttynotes.blogspot.com/2010/12/man-in-middle-fun-with-perl-lwp.html
• http://vttynotes.blogspot.com/2011/03/quick-note-on-lwp-and-perl-security-cve.html

If LWP::UserAgent::env_proxy is called in a CGI environment, the case-insensitivity when looking for "http_proxy" permits "HTTP_PROXY" to be found, but this can be trivially set by the web client using the "Proxy:" header.

The Net::HTTPS module in libwww-perl (LWP) before 6.00, as used in WWW::Mechanize, LWP::UserAgent, and other products, when running in environments that do not set the If-SSL-Cert-Subject header, does not enable full validation of SSL certificates by default, which allows remote attackers to spoof servers via man-in-the-middle (MITM) attacks involving hostnames that are not properly validated.

• http://vttynotes.blogspot.com/2010/12/man-in-middle-fun-with-perl-lwp.html
• http://vttynotes.blogspot.com/2011/03/quick-note-on-lwp-and-perl-security-cve.html

LWP::Protocol::file can open existent file from file:// scheme. However, current version of LWP uses open FILEHANDLE,EXPR and it has ability to execute arbitrary command

• https://github.com/libwww-perl/libwww-perl/pull/270