What you are thinking about there is perhaps implementation defined behavior, which is distinct from undefined behavior; and the sequence was the other way rou

What you are thinking about there is perhaps implementation defined behavior, which is distinct from undefined behavior; and the sequence was the other way round - hardware with different behaviors already existed, and not specifying them in the language allowed C to succeed because it wasn't tied to a particular machine. The answer is different for different kinds of undefined behavior, but spatial memory safety violations are basically always possible in a language you can write an OS in, since you need to convert from hardware buffers to higher level types. temporal memory safety wasn't possible to enforce at the time on a low level language, it's taken decades for it to be implemented in a mainstream non-garbage-collected language. Integer overerflow is still not caught by default even in rust for efficiency reasons (it would take all the processor vendors to implement an efficient way of catching it)