The No. 4 item on the OWASP top 10 is external XML entities. When using XML::Parser, XML::Simple is currently vulnerable by default.
To install XML::Simple, copy and paste the appropriate command in to your terminal.
cpanm
cpanm XML::Simple
CPAN shell
perl -MCPAN -e shell install XML::Simple
For more information on module installation, please visit the detailed CPAN module installation guide.