Comment by edelbitter

A rewrite would tackle the classic C-style W^X problems, at the expense of maintainability and focus on logic bugs and general oversights from inelegant (or lack of) design. And I'd bet PHP (and popular PHP software for reasons rooted in the language) still got plenty of the latter. You know, the "oops, that filename was client provided" kind of code execution that no amount of (un)safe blocks can help with.