RUSTSEC-2020-0101: conquer-once: conquer-once's OnceCell lacks Send bound for its Sync trait.

Description

Affected versions of conquer-once implements Sync for its OnceCell type without restricting it to Sendable types.

This allows non-Send but Sync types such as MutexGuard to be sent across threads leading to undefined behavior and memory corruption in concurrent programs.

The issue was fixed by adding a Send constraint to OnceCell.

More Info

https://github.com/oliver-giersch/conquer-once/issues/3

Patched Versions