Every perl editor which tries to check for compile time errors and warnings (Komodo, Padre, emacs with flyspell using perl -c, vi?) need to put use Safe upfront, and no Safe at the end of the BEGIN or the begin of INIT.
in reply to Re: Vulnerabilities when editing untrusted code...
in thread Vulnerabilities when editing untrusted code... (Komodo)
This cannot be done within Perl generally as users need to execute BEGIN blocks, just not in editors.
The only remaining problem with Safe is then XS code, which might get executed at compile-time and cannot be checked for harm.