RUSTSEC-2021-0048: stackvector: StackVec::extend can write out of bounds when size_hint is incorrect

Description

StackVec::extend used the lower and upper bounds from an Iterator's size_hint to determine how many items to push into the stack based vector.

If the size_hint implementation returned a lower bound that was larger than the upper bound, StackVec would write out of bounds and overwrite memory on the stack. As mentioned by the size_hint documentation, size_hint is mainly for optimization and incorrect implementations should not lead to memory safety issues.

More Info

https://github.com/Alexhuszagh/rust-stackvector/issues/2

Patched Versions