The difference I see there is any line in a C codebase could have these issues, whereas in Rust they're specifically marked as unsafe sections, with the language having a clear list of invariants it expects the programmer to uphold in an unsafe block. Additionally Rust has a culture of developers specifically justifying the unsafe block and why it's correct in comments. It's a massive reduction of the scope of the code that needs audited, that doesn't mean there can't be mistakes in it, just that it's easier to verify certain properties of the whole codebase.