If you're trying to simplify access to the CGI object, sharing $self outside of a class hierarchy is an ugly way to do it. You're mixing objects and procedural code, for one thing, in a way that's going to confuse things for others (or perhaps for yourself, after time has passed).

When people read

  sub somesub {
      my $self = shift;
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they expect that somesub is a legitimate object method, and not one that has been force-fed a reference to a class that is related only by way of common data members.

If you want to simplify access to a single CGI object, hide it behind a singleton or make it a global. Globals can be misused, but they have their places.