Smoltcp: A small TCP/IP stack in Rust
This is a really good example of the kind of safety benefit you get when using Rust: this is a fairly low-level piece of software (not a kernel, but I'd say it's lower-level than at least 80% of what's usually written) and yet, only 76 lines of codes are located inside unsafe blocks for the whole code-base. To be safe from memory vulnerabilities, all you need is audit theses 76 lines. It can still be a tough job, and bugs may slip past the review, but it's a huge improvement over having to audit thousands of lines.