How severe is GHSA-chgr-c6px-7xpp?

No CVSS score has been assigned to GHSA-chgr-c6px-7xpp yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-chgr-c6px-7xpp?

GHSA-chgr-c6px-7xpp affects the following packages: pyo3 (crates.io). Ecosystems affected: crates.io.

How do I fix GHSA-chgr-c6px-7xpp?

Update pyo3 to 0.29.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-chgr-c6px-7xpp is resolved across your whole dependency graph.

How do I detect GHSA-chgr-c6px-7xpp in my crates.io dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pyo3. 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-chgr-c6px-7xpp 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-chgr-c6px-7xpp?

O3 pinpoints whether GHSA-chgr-c6px-7xpp 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-chgr-c6px-7xpp actively exploited in the wild?

No public exploit code has been indexed for GHSA-chgr-c6px-7xpp 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-chgr-c6px-7xpp published, and has it been updated?

GHSA-chgr-c6px-7xpp was published on June 12, 2026 and was last updated on July 17, 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-chgr-c6px-7xpp

GHSA-chgr-c6px-7xpp is a security vulnerability in pyo3. O3 Security confirms whether GHSA-chgr-c6px-7xpp is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

PyO3 has a missing `Sync` bound on `PyCFunction::new_closure` closures

Also known asRUSTSEC-2026-0177

Published

Jun 12, 2026

Updated

Jul 17, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Blast Radius

1 pkg affected

🦀pyo3

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

PyCFunction::new_closure (and the temporary new_closure_bound complement in the 0.21–0.22 series) required the supplied closure to be Send + 'static but not Sync. The resulting PyCFunction is a Python callable that can be invoked from any Python thread, which means the closure may be called concurrently from multiple threads, and needs a Sync bound to prevent possible data races.

The problem exists under all Python versions but is particularly vulnerable under the newer free-threaded Python variant, which do not have serial execution imposed by the Global Interpreter Lock. Under releases protected by the GIL, the ability to "detach" from the Python interpreter temporarily inside the closure (e.g. by Python::detach) makes it possible for interleaved and/or concurrent execution of various portions of the closure.

PyO3 0.29.0 added a Sync bound to close this thread-safety bug.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🦀crates.io	`pyo3`	all versions	0.29.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pyo3. 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 pyo3 to 0.29.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-chgr-c6px-7xpp 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-chgr-c6px-7xpp 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-chgr-c6px-7xpp. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

`PyCFunction::new_closure` (and the temporary `new_closure_bound` complement in the 0.21–0.22 series) required the supplied closure to be `Send + 'static` but not `Sync`. The resulting `PyCFunction` is a Python callable that can be invoked from any Python thread, which means the closure may be called concurrently from multiple threads, and needs a `Sync` bound to prevent possible data races. The problem exists under all Python versions but is particularly vulnerable under the newer free-threaded Python variant, which do not have serial execution imposed by the Global Interpreter Lock. Under r

O3 Security · Impact-Aware SCA

Is GHSA-chgr-c6px-7xpp in your dependencies?

O3 detects GHSA-chgr-c6px-7xpp 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.

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