Advisories for Cargo/Pyo3 package

The family of functions to read "borrowed" values from Python weak references were fundamentally unsound, because the weak reference does itself not have ownership of the value. At any point the last strong reference could be cleared and the borrowed value would become dangling. In PyO3 0.22.4 these functions have all been deprecated and patched to leak a strong reference as a mitigation. PyO3 0.23 will remove these functions entirely.

The family of functions to read "borrowed" values from Python weak references were fundamentally unsound, because the weak reference does itself not have ownership of the value. At any point the last strong reference could be cleared and the borrowed value would become dangling. In PyO3 0.22.4 these functions have all been deprecated and patched to leak a strong reference as a mitigation. PyO3 0.23 will remove these functions entirely.

An issue was discovered in the pyo3 crate before 0.12.4 for Rust. There is a reference-counting error and use-after-free in From<Py>.