It's not a tag but a keyword search. I don't know projects entirely written in Rust (other than single crates) to look for (by name). So probably there are more Rust-based vulnerabilities around than the ones from the Mitre query from the link.

And yes, edge-cases are the worst. The only concern is that these vulnerabilities were introduced by people who know the language more than anyone (I'd like to think that patches mainlined into std are written, revised and maintained by the best Rust developers). I'm afraid to imagine what kind of vulnerabilities could a person like me introduce in my own Rust programs.

That's the point of splitting Rust into safe and unsafe. If you're not trusting yourself with C-like danger, then stick to writing safe Rust. When you need to do something risky, then it will require unsafe{} blocks, which are a signal to be extra careful, and stand out in code reviews.

Also keep in mind that std is in unusual position, because it provides the unsafe foundation for safe programs. For example, you as a Rust user can't cause any memory unsafety when using the String type, but std had to define it for you from unsafe primitives. This concept of building safe abstraction from unsafe primitives is similar to Python: CPython is written in an unsafe language, but this unsafety is hidden from Python programs.