The only thing that gets me is the starting point, namely this template file. The fact that you're getting the name of the file directly from the CGI QUERY_STRING, even with all the various s/// operators in there, can still *possibly* leave you open for the "; rm -rf /" attacks. You may have that fixed, but for some reason that concerns me.

Here's my suggestion: Since this appears to be selecting a template file from a limited number of choices, how about creating a hash that maps a template keyword to the actual filename that you use, so that the open call will only see a filename that *you* specify and doesn't at all come from the CGI query. The only major check you'll need is to add a default option if the template keyword parameter is not in your hash, but this is trivial. eg:

my %template_hash = ( default  => "www/default.tmp",
                      detailed => "www/detail.tmp",
                      brief    => "www/brief.tmp" );

# $temp still gotten as before, could also be cgi->param
my $template_file = ( defined $template_hash{ $temp } ) ?
    $template_hash{ $temp } : $template_hash{ 'default' };

# Continue on as above.
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