A “letters only” filter counted characters, not bytes, in a practice challenge

A “letters only” filter counted characters, not bytes. Invisible bytes got through in a practice challenge on YesWeHack Dojo.

Sources: Self-published write-up on DEV (6 Oct) · Note: This is a self-published write-up of a deliberately vulnerable practice challenge, not a real product. No live systems or victims are involved, and CTN is not publishing a how-to.