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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-4q83-7cq4-p6wg can be triaged on real exposure rather than presence alone.

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 September 10, 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

Not in CISA KEV

GHSA-4q83-7cq4-p6wg — tokio

GHSA-4q83-7cq4-p6wg is a security vulnerability in tokio. A fix is available for tokio — see the affected versions and patch details below.

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

Also known asRUSTSEC-2023-0005

Published

Feb 4, 2023

Updated

Sep 10, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Sep 10, 2026 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

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`cargo update -p tokio --precise 1.24.2`
🦀crates.io	`tokio`	≥ 1.19.0&&< 1.20.4	1.20.4`cargo update -p tokio --precise 1.20.4`
🦀crates.io	`tokio`	≥ 0.2.0&&< 1.18.5	1.18.5`cargo update -p tokio --precise 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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-4q83-7cq4-p6wg can be triaged on real exposure rather than presence alone.

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 Security finds GHSA-4q83-7cq4-p6wg across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

Scan my dependencies How O3 SCA works