GHSA-mc9m-6fm9-pghc: Race Condition

Published Aug 20, 2026
·
Updated

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 getenv 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 Software

2 affected componentsFixes available
rust/kcl-lib<0.2.153
0.2.153
pip/zoo-kcl<0.3.153
0.3.153

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade rust/kcl-lib to a version that resolves this vulnerability.

    Fixed in 0.2.153
  2. Upgrade

    Upgrade pip/zoo-kcl to a version that resolves this vulnerability.

    Fixed in 0.3.153

Event History

Aug 20, 2026
Advisory Published
via GitHub·06:34 PM
Data Sourced
via GitHub·06:34 PM
DescriptionWeaknessAffected Software

Frequently Asked Questions

1

Which software packages should be reviewed for exposure?

Review deployments using rust/kcl-lib or pip/zoo-kcl. No affected or fixed version ranges are provided.

2

What runtime condition is required for the issue to occur?

The condition requires concurrent environment access: a get_env operation must use a previously loaded buffer pointer while another operation causes the environment Vec to reallocate. This can cause the read to use freed memory and return a stale or corrupted environment object.

Contact

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