RUSTSEC-2020-0121: AtomicBox<T> implements Send/Sync for any `T: Sized`

What to do

1. See which version you have: cargo tree -i abox (it also shows which of your dependencies pulls it in).
2. Update within your version requirement: cargo update -p abox. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for example abox = "0.4.1") or update the dependency that pulls it in.
3. Check again with cargo audit, or paste your Cargo.lock into our Cargo.toml checker.

Details from the advisory

Affected versions of this crate implements Send/Sync for AtomicBox<T> without requiring T: Send/T: Sync. This allows to create data races to T: !Sync and send T: !Send to another thread.

Such behavior breaks the compile-time thread safety guarantees of Rust, and allows users to incur undefined behavior using safe Rust (e.g. memory corruption from data race).

The flaw was corrected in commit 34c2b9e by adding trait bound T: Send to Send impl for AtomicBox<T> and trait bound T: Sync to Sync impl for AtomicBox<T>.

References

• Package: crates.io/crates/abox
• Advisory: rustsec.org/advisories/RUSTSEC-2020-0121.html
• Report: github.com/SonicFrog/abox/issues/1

From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.