Swift: A memory-safer systems programming language: https://www.swift.org
Firebloom: A memory-safer C variant: https://support.apple.com/en-il/guide/security/sec30d8d9ec1/...
Not sure what the answer is for existing memory-unsafe code.
It's an engineering approach that involves writing "A buffer overflow issue was addressed with improved memory handling" an awful lot. Hopefully one day they will finish improving the memory handling!
General purpose languages, whether that's something like C or Rust or even Javascript are not the appropriate tool. Turing Completeness is a bad idea from a security point of view, not a wonderful feature.
Well, of course the real issue was the car crash. But wearing a seatbelt would have sure helped!
In Rust we can't trivially write a bounds miss by mistake. But in WUFFS we just can't write a bounds miss at all. Like, that's not a thing in WUFFS, it doesn't compile. You can write your own bounds checks and show WUFFS that works, or you can write code which clearly can't have a bounds miss with no checks, that works too. But you can't just "forget" or "screw up" those won't compile.
This would be frustrating in a general purpose language. WUFFS doesn't have a "Hello, World" program because it lacks both strings and the idea of outputing to the screen. But WUFFS isn't a general purpose language, however it's the correct way to write the code that takes image files we got from some dubious source and processes them.
When Apple announced they wanted to provide proper security for vulnerable iPhone users, this is what that would look like coming from a company which actually cared about security. What you got is what it looks like from a company which prioritised marketing.