On using C from the creators of curl:

> We count about 40% of our security vulnerabilities to date to have been the direct result of us using C instead of a memory-safe language alternative. (https://daniel.haxx.se/blog/2025/04/07/writing-c-for-curl)

And, like what I was referring to, it is even more difficult to prove the absence of memory safety issues entirely. We have only managed to actually prove it for a handful of non-trivial programs, like the seL4 microkernel.

Now, this is all an entirely different question to whether the extra work required to write your program in Rust to avoid memory safety problems is actually worthwhile. If you are writing a program with no networking code, no privilege escalation, and no confidential information, the answer is probably that it doesn't matter. If a game has a buffer overflow in some weird edge case, it doesn't really matter. If your data processing code has a problem, you can probably spot that and it probably won't lead to any security concerns. If your file system scanner runs into a memory safety issue, it probably won't negatively impact you that much.

But if your crypto library has memory safety problems, you are in for a bad time.