# CVE-2026-120438: QuickJS-NG before 0.16.0 Heap Buffer Overflow via Proxy ownKeys Enumeration

Status: published. Published: 2026-11-02. Updated: 2026-11-02.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- quickjs-ng / QuickJS-NG (quickjs-ng/quickjs): ≥ 0; < 0.16.0 (affected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 8.5 (high); CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 7.8 (high); CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-190

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/quickjs-ng/quickjs/security/advisories/GHSA-jp52-chwg-2p9p (CNA: VulnCheck; vendor-advisory)

- https://github.com/quickjs-ng/quickjs/commit/252209d99cf112568160548bdcaa98d95e0d0068 (CNA: VulnCheck; patch)

- https://github.com/quickjs-ng/quickjs/releases/tag/v0.16.0 (CNA: VulnCheck; release-notes)

- https://github.com/quickjs-ng/quickjs/blob/v0.15.1/quickjs.c#L51509 (CNA: VulnCheck; technical-description)

- https://www.vulncheck.com/advisories/quickjs-ng-before-0.16.0-heap-buffer-overflow-via-proxy-ownkeys-enumeration (CNA: VulnCheck; third-party-advisory)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-120438; retrieved 2026-11-02; source updated 2026-11-02

Revision: c195b26f1db618bcfcf896d2f9e137bdf32ecf333773fefbf075f561dffc3d58

Canonical: https://y2.dev/cve/CVE-2026-120438

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.