There are no "safe" languages. Fast managed languages JIT compile your code to the same unsafe machine code as C, and JITs frequently have exploitable bugs. Most (all?) of the techniques which help mitigate safety bugs in "unsafe" languages also help or can be used to help mitigate safety bugs in JITs. And then there's all the standard library functions implemented in "unsafe" languages.

Then there's Rust, which doesn't even claim to be a safe language. It claims to (and does a good job at!) containing the unsafety to certain parts of the code, which is nice but there's still a whole lot of code that's marked unsafe which benefits from these mitigations.