The libwww-perl LWP::Protocol::https module 6.04 through 6.06 for Perl, when using IO::Socket::SSL as the SSL socket class, allows attackers to disable server certificate validation via the (1) HTTPS_CA_DIR or (2) HTTPS_CA_FILE environment variable.
http://www.openwall.com/lists/oss-security/2014/05/06/8