How severe is GHSA-mc9m-6fm9-pghc?

No CVSS score has been assigned to GHSA-mc9m-6fm9-pghc yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-mc9m-6fm9-pghc?

GHSA-mc9m-6fm9-pghc affects the following packages: kcl-lib (crates.io), zoo-kcl (PyPI). Ecosystems affected: crates.io, PyPI.

How do I fix GHSA-mc9m-6fm9-pghc?

Update kcl-lib to 0.2.153 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mc9m-6fm9-pghc is resolved across your whole dependency graph.

How do I detect GHSA-mc9m-6fm9-pghc in my crates.io, PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for kcl-lib, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-mc9m-6fm9-pghc if there is no patch (or I can't update yet)?

Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable.

Is GHSA-mc9m-6fm9-pghc actively exploited in the wild?

No public exploit code has been indexed for GHSA-mc9m-6fm9-pghc 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-mc9m-6fm9-pghc published, and has it been updated?

GHSA-mc9m-6fm9-pghc was published on August 20, 2026 and was last updated on August 20, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

GHSA-mc9m-6fm9-pghc: Fixed in 0.2.153

Real-World Exposure

2 pkgs affected

🦀kcl-lib🐍zoo-kcl

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

Description

A race condition in kcl-lib can result in a use-after-free when accessing environments concurrently. During Vec reallocation, the previous buffer containing Box pointers is freed and replaced. A concurrent get_env operation that has already loaded a pointer to the old buffer may subsequently index into freed memory and retrieve a stale or corrupted Pin<Box<Environment>>.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🦀crates.io	`kcl-lib`	all versions	0.2.153`cargo update -p kcl-lib --precise 0.2.153`
🐍PyPI	`zoo-kcl`	all versions	0.3.153`pip install --upgrade 'zoo-kcl==0.3.153'`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for kcl-lib, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update kcl-lib to 0.2.153 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mc9m-6fm9-pghc is resolved across your whole dependency graph.
Workarounds
Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable.

Frequently Asked Questions

A race condition in kcl-lib can result in a use-after-free when accessing environments concurrently. During Vec reallocation, the previous buffer containing Box pointers is freed and replaced. A concurrent get_env operation that has already loaded a pointer to the old buffer may subsequently index into freed memory and retrieve a stale or corrupted Pin<Box<Environment>>.

O3 Security · Impact-Aware SCA

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