Rust advisories / async-coap
Vulnerability HighRUSTSEC-2020-0124 · async-coap
RUSTSEC-2020-0124: ArcGuard's Send and Sync should have bounds on RC
Short answerA security vulnerability in the async-coap crate: ArcGuard's Send and Sync should have bounds on RC. High severity (CVSS 8.1). No fixed version: replace the crate or remove the affected code path.
| Crate | async-coap |
|---|---|
| Type | Vulnerability (memory-corruption, thread-safety) |
| Affected versions | Every version. |
| Fixed in | none |
| Severity | High, CVSS 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H |
| Published | 2020-12-08 |
| Last changed | 2023-11-08 |
| Also known as | CVE-2020-36444, GHSA-9j8q-m9x5-9g6j |
What to do
- Find who pulls it in:
cargo tree -i async-coap. - Avoid the affected API, or replace the crate.
Details from the advisory
Affected versions of this crate implement Send/Sync for ArcGuard<RC, T> with no trait bounds on RC. This allows users to send RC: !Send to other threads and also allows users to concurrently access Rc: !Sync from multiple threads.
This can result in memory corruption from data race or other undefined behavior caused by sending T: !Send to other threads (e.g. dropping MutexGuard<T> in another thread that didn't lock its mutex).
References
- Package: crates.io/crates/async-coap
- Advisory: rustsec.org/advisories/RUSTSEC-2020-0124.html
- Report: github.com/google/rust-async-coap/issues/33
From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.
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