You don't really have to worry about any of this if you use a proper interpreter for your configuration files (for example, if you do configuration by embedding

You don't really have to worry about any of this if you use a proper interpreter for your configuration files (for example, if you do configuration by embedding Lua in your application, which is very common and useful). If you try to build up a programming language from scratch, you're right that you're going to have problems, but embedding a battle-tested, safe language means you don't have to worry about your program being put in "literally any state" or your program being susceptible to buffer overflows.