The Net::Netmask module before 2.0000 for Perl does not properly consider extraneous zero characters at the beginning of an IP address string, which (in some situations) allows attackers to bypass access control that is based on IP addresses.
To install Net::Netmask, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Net::Netmask
CPAN shell
perl -MCPAN -e shell install Net::Netmask
For more information on module installation, please visit the detailed CPAN module installation guide.