Maybe list out my dependencies and spend one day a week auditing the most-risky, least-popular ones? Random audits where I make sure that my vendored dependencies or files like Cargo.lock haven't changed when I wasn't looking?
Do something like Firefox did with Graphite, and compile as many dependencies as possible into a webasm sandbox so they can't do I/O?
Years ago I thought "Haskell's I/O discipline is cool, but man it looks inconvenient..." Now I wonder if that will become the mandate for new languages. I imagine it's hard to enforce in native code. At least Rust has a strong foundation for both running, and running as, wasm, so maybe in the future it'll be easy to say "Run this function / these functions in a sandbox, nevermind the cost, and write all the glue code for me."
Ironicially, a webasm runtime, especially if it has a JIT, is far too large a project for me to audit on company time... but at least it's also very popular.