GHSA-mc9m-6fm9-pghc: Zoo Design Studio Memory-corruption Vulnerability

MODERATE
Share
CWE-362 CWE-416
Published
Advisory Summary

GHSA-mc9m-6fm9-pghc is a MODERATE memory-corruption vulnerability (CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')) affecting Zoo Design Studio libraries in the PyPI ecosystem. The issue involves memory-corruption in memory handling of lib-kcl. Remediation is available by upgrading affected packages to version 0.3.153, 0.2.153.

GHSA-mc9m-6fm9-pghc at a Glance

CVE Identifier N/A
GHSA Identifier GHSA-mc9m-6fm9-pghc
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Affected Product Zoo Design Studio
Package Ecosystem PyPI
Published Date
Last Updated

How to Fix GHSA-mc9m-6fm9-pghc

To remediate this vulnerability, upgrade all affected Zoo Design Studio dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

zoo-kcl fixed: 0.3.153 
pip install zoo-kcl>=0.3.153
kcl-lib fixed: 0.2.153 
Upgrade kcl-lib to 0.2.153
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show zoo-kcl

How to Check if You Are Affected

To determine whether your Python environment is affected by GHSA-mc9m-6fm9-pghc, inspect your installed packages using pip:

pip show zoo-kcl

Analyze the terminal output to locate any version of Zoo Design Studio in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.3.153), your application is affected.

Note: The pip show zoo-kcl command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition'), where the product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently. In Zoo Design Studio, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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>>.

GHSA-mc9m-6fm9-pghc Affected Zoo Design Studio Versions

2 component(s)
Fixed Versions:
0.3.1530.2.153
Product / Package Ecosystem Affected Versions Fixed Version
zoo-kcl
pypi/zoo-kcl
PyPI
< 0.3.153
0.3.153
kcl-lib
 crates.io
< 0.2.153
0.2.153

References

GitHub Advisory / Wiki ADVISORY
https://github.com/KittyCAD/modeling-app/security/advisories/GHSA-mc9m-6fm9-pghc
Zoo Design Studio Source Repository REPOSITORY
https://github.com/KittyCAD/modeling-app

Frequently Asked Questions

What is GHSA-mc9m-6fm9-pghc?
GHSA-mc9m-6fm9-pghc is a security vulnerability in Zoo Design Studio involving Memory-corruption in memory handling of lib-kcl under CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition').
Which Zoo Design Studio versions are affected?
Affected versions include releases prior to 0.3.153, 0.2.153 across affected packages: zoo-kcl, kcl-lib.
What version fixes GHSA-mc9m-6fm9-pghc?
Upgrading to 0.3.153, 0.2.153 (or the latest patched release for your respective branch) resolves the vulnerability.
Is zoo-kcl affected?
Yes, zoo-kcl is affected in releases prior to 0.3.153. Upgrade your dependency to 0.3.153 or later.
Is kcl-lib affected?
Yes, kcl-lib is affected in releases prior to 0.2.153. Upgrade your dependency to 0.2.153 or later.
What CWE is associated with GHSA-mc9m-6fm9-pghc?
GHSA-mc9m-6fm9-pghc is classified under CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') (The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.).
How can I check PyPI dependencies for GHSA-mc9m-6fm9-pghc?
Run the dependency tree command: 'pip show zoo-kcl'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-mc9m-6fm9-pghc",
  "modified" : "2026-08-20T18:34:11Z",
  "published" : "2026-08-20T18:34:11Z",
  "aliases" : [ ],
  "summary" : "Zoo Design Studio: Memory-corruption in memory handling of lib-kcl",
  "details" : "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>>.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "zoo-kcl"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.3.153"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "kcl-lib"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.2.153"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/KittyCAD/modeling-app/security/advisories/GHSA-mc9m-6fm9-pghc"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/KittyCAD/modeling-app"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-362", "CWE-416" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-08-20T18:34:11Z",
    "nvd_published_at" : null
  }
}