---
id: "CVE-2026-120438"
kind: "vulnerability"
aliases: ["CVE-2026-120438"]
title: "QuickJS-NG: integer overflow in Proxy handling lets scripts corrupt memory"
severity: "high"
cvss: 8.5
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["32-bit", "embedded-javascript", "quickjs-ng", "runtime"]
not_affected_if: ["64-bit-host", "trusted-code-only", "version-0.16.0-or-later"]
published_at: "2026-11-02T15:17:25+00:00"
first_seen_at: "2026-11-02T15:24:02+00:00"
updated_at: "2026-11-02T15:25:54+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-120438", "first_seen_at": "2026-11-02T15:24:02+00:00"}]
---

# QuickJS-NG: integer overflow in Proxy handling lets scripts corrupt memory

QuickJS-NG versions before 0.16.0 have an integer overflow in js_proxy_get_own_property_names() that causes a heap buffer overflow on 32-bit hosts. An attacker who can run JavaScript can crash the process or possibly execute code by returning a large array-like object from a Proxy ownKeys trap.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the QuickJS-NG version in use; anything below `0.16.0` is in the affected range.
- Confirm whether the host is a 32-bit build, since the sources describe the overflow on 32-bit hosts.
- Check whether untrusted scripts can run in the embedding application.

## Fix

- QuickJS-NG: upgrade to `0.16.0` or later.

## Timeline

- 2026-11-02T15:24:02+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-120438

## Documents

- [advisory] Vendor advisory: github.com https://github.com/quickjs-ng/quickjs/security/advisories/GHSA-jp52-chwg-2p9p
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/quickjs-ng-before-0.16.0-heap-buffer-overflow-via-proxy-ownkeys-enumeration
- [fix] Patch: github.com https://github.com/quickjs-ng/quickjs/commit/252209d99cf112568160548bdcaa98d95e0d0068
- [fix] Release notes: github.com https://github.com/quickjs-ng/quickjs/releases/tag/v0.16.0

## From the sources

QuickJS-NG before 0.16.0 contains an integer overflow in js_proxy_get_own_property_names() in quickjs.c that causes a heap buffer overflow on 32-bit hosts. Attackers running JavaScript can return a large array-like object from a Proxy ownKeys trap to wrap the allocation size, causing crashes or potential code execution.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_