How severe is GHSA-4q83-7cq4-p6wg?

No CVSS score has been assigned to GHSA-4q83-7cq4-p6wg yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-4q83-7cq4-p6wg?

GHSA-4q83-7cq4-p6wg affects the following packages: tokio (crates.io), tokio (crates.io), tokio (crates.io). Ecosystems affected: crates.io.

How do I fix GHSA-4q83-7cq4-p6wg?

Update tokio to 1.24.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4q83-7cq4-p6wg is resolved across your whole dependency graph.

How do I detect GHSA-4q83-7cq4-p6wg in my crates.io dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for tokio. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-4q83-7cq4-p6wg if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-4q83-7cq4-p6wg?

O3 pinpoints whether GHSA-4q83-7cq4-p6wg is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-4q83-7cq4-p6wg actively exploited in the wild?

No public exploit code has been indexed for GHSA-4q83-7cq4-p6wg yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was GHSA-4q83-7cq4-p6wg published, and has it been updated?

GHSA-4q83-7cq4-p6wg was published on February 4, 2023 and was last updated on February 4, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🦀 crates.io

GHSA-4q83-7cq4-p6wg

`tokio::io::ReadHalf<T>::unsplit` is Unsound

Also known asRUSTSEC-2023-0005

Published

Feb 4, 2023

Updated

Feb 4, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Blast Radius

3 pkgs affected

🦀tokio🦀tokio🦀tokio

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.

Description

tokio::io::ReadHalf<T>::unsplit can violate the Pin contract

The soundness issue is described in the tokio/issues#5372

Specific set of conditions needed to trigger an issue (a !Unpin type in ReadHalf) is unusual, combined with the difficulty of making any arbitrary use-after-free exploitable in Rust without doing a lot of careful alignment of data types in the surrounding code.

The tokio feature io-util is also required to be enabled to trigger this soundness issue.

Thanks to zachs18 reporting the issue to Tokio team responsibly and taiki-e and carllerche appropriately responding and fixing the soundness bug.

Tokio before 0.2.0 used futures 0.1 that did not have Pin, so it is not affected by this issue.

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
🦀crates.io	`tokio`	≥ 1.21.0&&< 1.24.2	1.24.2
🦀crates.io	`tokio`	≥ 1.19.0&&< 1.20.4	1.20.4
🦀crates.io	`tokio`	≥ 0.2.0&&< 1.18.5	1.18.5

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for tokio. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update tokio to 1.24.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4q83-7cq4-p6wg is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-4q83-7cq4-p6wg is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-4q83-7cq4-p6wg. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

`tokio::io::ReadHalf<T>::unsplit` can violate the `Pin` contract The soundness issue is described in the [tokio/issues#5372](https://github.com/tokio-rs/tokio/issues/5372) Specific set of conditions needed to trigger an issue (a !Unpin type in ReadHalf) is unusual, combined with the difficulty of making any arbitrary use-after-free exploitable in Rust without doing a lot of careful alignment of data types in the surrounding code. The `tokio` feature `io-util` is also required to be enabled to trigger this soundness issue. Thanks to zachs18 reporting the issue to Tokio team responsibly and

O3 Security · Impact-Aware SCA

Is GHSA-4q83-7cq4-p6wg in your dependencies?

O3 detects GHSA-4q83-7cq4-p6wg across crates.io dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works