Affected versions of this crate unconditionally implemented Send & Sync for types PinSlab<T> & Unordered<T, S>. This allows sending non-Send types to other threads and concurrently accessing non-Sync types from multiple threads.

This can result in a data race & memory corruption when types that provide internal mutability without synchronization are contained within PinSlab<T> or Unordered<T, S> and accessed concurrently from multiple threads.

The flaw was corrected in commits 92f40b4 & 6a6c367 by adding trait bound T: Send to Send impls for PinSlab<T> & Unordered<T, S> and adding T: Sync to Sync impls for PinSlab<T> & Unordered<T, S>.

References

• udoprog/unicycle#8
• udoprog/unicycle@6a6c367
• udoprog/unicycle@92f40b4
• https://rustsec.org/advisories/RUSTSEC-2020-0116.html