Others have answered the OP's original question about security but can I please ask people to stop promolgating this... 
s/$this/qq{qq{$with}}/eeg;

[download]
It's wrong (even assuming $with can be trusted not to be malicious). It breaks even if $with contains an innocent closing brace. If you want to do this it's more resilient with a here doc. 
s{$this}{
  chop( my $r = eval "<<_END_\n$with\n_END_" );
  die $@ if $@;
  $r;
}eg;

[download]

In reply to Re: Security with /ee modifier by nobull
in thread Security with /ee modifier by richard5mith

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