My servers use proprietary protocols and one of the first thing my protocol handlers do is check validity of the input. You will not find generic "read until EOL/Whatever" in my code. The low level logic knows exactly what to expect at each point and how to validate it. All over encrypted connection.

Good luck hiring dedicated expert or team willing to break it. I am not Google and cost of trying to break my software where it matters far exceeds any potential benefits.

So sure, I am not the a prime choice as security target which makes it even better.