perl -MCGI=param -le "print for param('title')" ?title=foo;title=bar
foo
bar

##</code><code>##

use strict;
use Data::Dumper;
use CGI;

my $q = CGI->new('?title=foo;title=bar;title=injected_key;title=injected_value');

my $query = { title => $q->param('title') };

print Dumper $query;
__END__
# Outputs:

$VAR1 = {
          'injected_key' => 'injected_value',
          'title' => 'bar'
        };