> Or Forth with scientific library, bound to the constraints. Put some HTTP library on top and some easy HTML interface from a browser with no JS/CSS3 support at all. It will look rusty but unexploitable.

Let this be a lesson to you youngsters that nothing in unexploitable.

Forth has no standard library for interfacing with SQLite or any other database. You're either using 8th or the C ABI. Therefore, you'll most likely be concatenating SQL queries. Are you disciplined enough to make that properly secure? Do you know all the intricacies?