see this: https://metacpan.org/pod/distribution/CGI/lib/CGI.pod#CGI.pm-HAS-BEEN-REMOVED-FROM-THE-PERL-CORE

If you upgrade to a new version of perl or if you rely on a system or vendor perl and get an updated version of perl through a system update, then you will have to install CGI.pm yourself with cpan/cpanm/a vendor package/manually.

(i would suggest reading the entire section)

CGI.pm doesn't have to be replaced to keep your application working, it just needs to be a separately installed module once perl has been upgraded by your host (to or beyond 5.22, see below).

therefore i wouldn't necessarily recommend replacing CGI.pm on an existing application.

this is some CPAN documentation on CGI alternatives [metacpan.org]


this (the removal of CGI.pm from the perl core) has been discussed in the perl programming lists since 2013:
[nntp.perl.org...]

I think it's time to seriously consider removing CGI.pm from the core distribution. It is no longer what I'd point *anyone* at for writing *any* sort of web code. It is in the core, as far as I know, because once it was the state of the art, and a major reason for many people to use the language. I don't think either is true now.

ouch! (the truth hurts...)

CGI.pm was removed from the perl core in perl 5.22:
https://perldoc.perl.org/perl5220delta#Removed-Modules-and-Pragmata

perl 5.22 was released june 1, 2015:
[nntp.perl.org...]