Vulnerability MediumRUSTSEC-2021-0072 · tokio
RUSTSEC-2021-0072: Task dropped in wrong thread when aborting `LocalSet` task
Short answerA security vulnerability in the tokio crate: Task dropped in wrong thread when aborting `LocalSet` task. GitHub rates it Medium. Fixed in 1.5.1, 1.6.3, 1.7.2, 1.8.1: update to a fixed version.
| Crate | tokio |
|---|---|
| Type | Vulnerability (memory-corruption) |
| Affected versions | From 0.3.0 before 1.5.1; from 1.6.0 before 1.6.3; from 1.7.0 before 1.7.2; from 1.8.0 before 1.8.1. |
| Fixed in | 1.5.1, 1.6.3, 1.7.2, 1.8.1 |
| Severity | Medium (GitHub rating) |
| Published | 2021-07-07 |
| Last changed | 2023-11-08 |
| Also known as | CVE-2021-38191, GHSA-2grh-hm3w-w7hv |
| Affected functions | tokio::task::JoinHandle::abort |
What to do
- See which version you have:
cargo tree -i tokio(it also shows which of your dependencies pulls it in). - Update within your version requirement:
cargo update -p tokio. If the fix is a newer major or minor than your requirement allows, raise it in Cargo.toml (for exampletokio = "1.8.1") or update the dependency that pulls it in. - Check again with
cargo audit, or paste your Cargo.lock into our Cargo.toml checker.
Details from the advisory
When aborting a task with JoinHandle::abort, the future is dropped in the thread calling abort if the task is not currently being executed. This is incorrect for tasks spawned on a LocalSet.
This can easily result in race conditions as many projects use Rc or RefCell in their Tokio tasks for better performance.
See tokio#3929 for more details.
References
- Package: crates.io/crates/tokio
- Advisory: rustsec.org/advisories/RUSTSEC-2021-0072.html
- Report: github.com/tokio-rs/tokio/issues/3929
From the RustSec Advisory Database (CC0-1.0) via the OSV export, downloaded Oct 24, 2026. Severity score computed from the published CVSS vector.
Other advisories for tokio
- VulnerabilityRUSTSEC-2021-0124 · 2021-11-16Data race when sending and receiving after closing a `oneshot` channel
- VulnerabilityRUSTSEC-2023-0001 · 2023-01-04reject_remote_clients Configuration corruption
- UnsoundRUSTSEC-2023-0005 · 2023-01-11`tokio::io::ReadHalf<T>::unsplit` is Unsound
- UnsoundRUSTSEC-2025-0023 · 2025-04-07Broadcast channel calls clone in parallel, but does not require `Sync`
- VulnerabilityRUSTSEC-2026-0384 · 2026-10-21Race condition in `tokio::time::Interval` on Tokio v1.54.0
- UnsoundRUSTSEC-2026-0386 · 2026-10-13`AsyncFd::new` and related constructors violate I/O safety
Up next
Same cratetokio: security historyEvery advisory for this crate, and whether it is safe to use today.Read it next →Did this answer your question?