CSS hacks blow me away! Just a little tiny bit of user control, and a bad actor can slip-in a background-image that points to a remote gif that triggers a script-kiddie rig that does who-knows-what 🤯
I think that every hack out of there is the subversion of normal input. You're not creating a new entity, you just inserting something not expected which can trigger an abnormal response from an existing one.
I'm also a creator and the only things that were ever interesting for me in pen testing were reverse engineering and programming rootkits. Both because you have to set yourself to learning mode. It's like exploring those portions of the map where it's marked "Here be dragons".
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.