crossbeam-utils provides atomics, synchronization primitives, scoped threads, and other utilities for concurrent programming in Rust. crossbeam-utils prior to version 0.8.7 incorrectly assumed that the alignment of `{i,u}64` was always the same as `Atomic{I,U}64`. However, the alignment of `{i,u}64` on a 32-bit target can be smaller than `Atomic{I,U}64`. This can cause unaligned memory accesses and data race. Crates using `fetch_*` methods with `AtomicCell<{i,u}64>` are affected by this issue. 32-bit targets without `Atomic{I,U}64` and 64-bit targets are not affected by this issue. This has been fixed in crossbeam-utils 0.8.7. There are currently no known workarounds.
The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.
| Link | Tags |
|---|---|
| https://github.com/crossbeam-rs/crossbeam/security/advisories/GHSA-qc84-gqf4-9926 | third party advisory exploit |
| https://github.com/crossbeam-rs/crossbeam/pull/781 | patch third party advisory issue tracking |
| https://github.com/crossbeam-rs/crossbeam/releases/tag/crossbeam-utils-0.8.7 | third party advisory patch |