Exactly - the language isn't memory-safe. Instead it's effectively (implicitly!) relying on the fact that it runs on an abstract machine that has certain memory-safety properties. By contrast, a memory-safe language like C# is defined to be running on a memory-safe abstraction (the CLR, or more generally anything that faithfully implements the Microsoft intermediate language), while a memory-safe language like Rust either proves behaviour via the type system (no null pointers, no use after free) or inserts runtime checks (no out-of-bounds array accesses, panic on out-of-memory).