CVE-2026-120438

QuickJS-NG before 0.16.0 Heap Buffer Overflow via Proxy ownKeys Enumeration

8.5 HighFix available

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.

Attack profile

How easy it is to exploit

Attack vector: Local
Complexity: Low
Privileges needed: Low
User interaction: None

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: High

Exploit likelihood

0.14%Unchanged since Nov 3, 2026

What each source reports

CVE List Score used 8.5

QuickJS-NG before 0.16.0 Heap Buffer Overflow via Proxy ownKeys Enumeration

Record: CVE-2026-120438
CVSS 4.0: 8.5 HighCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS 3.1: 7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness: CWE-190
Updated: 2026-11-05

EUVDEUVD-2026-115198 8.5

Record: EUVD-2026-115198
CVSS 4.0: 8.5 HighCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Updated: 2026-11-05

GitHub AdvisoriesGHSA-m9xj-cppc-fm6c 8.5

QuickJS-NG before 0.16.0 contains an integer overflow in js_proxy_get_own_property_names() in...

Record: GHSA-m9xj-cppc-fm6c
CVSS 4.0: 8.5 HighCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness: CWE-190
Updated: 2026-11-02

NVD 8.5

Record: CVE-2026-120438
CVSS 4.0: 8.5 HighCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness: CWE-190
Updated: 2026-11-05

OSV 8.5

QuickJS-NG before 0.16.0 Heap Buffer Overflow via Proxy ownKeys Enumeration

Record: CVE-2026-120438
CVSS 4.0: 8.5 HighCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Weakness: CWE-190
Updated: 2026-11-07

OSVDEBIAN-CVE-2026-120438 8.5

Record: DEBIAN-CVE-2026-120438
CVSS 4.0: 8.5 HighCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Updated: 2026-11-06

OSVUBUNTU-CVE-2026-120438 8.5

Record: UBUNTU-CVE-2026-120438
CVSS 4.0: 8.5 HighCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS 3.1: 7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated: 2026-11-05

Affected products

quickjs-ng

Affected packages

Affected packages
Package	Affected	Fixed
`quickjs-ng` Debian:14	before 0.16.2-1, plus listed versions 0.13.0-10.13.0-20.13.0-30.14.0-10.14.0-2 Show 6 moreShow less 0.14.0-2~bpo13+10.14.0-2~bpo13+20.15.0-10.15.0-1~bpo13+10.15.1-10.15.1-1~bpo13+1	0.16.2-1
`quickjs-ng` Ubuntu:26.10	All versions, plus listed versions 0.15.0-10.15.1-10.16.2-2	None known

History

History
Recorded	Changed	Sources
Nov 6, 2026	affected, aliases, facts, references	CVE List, EUVD, NVD, OSV
Nov 4, 2026	affected, aliases, references	OSV
Nov 4, 2026	facts	EUVD, OSV
Nov 3, 2026	aliases, references	NVD, OSV
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-120438 is a high vulnerability (CVSS 8.5) in Quickjs-ng, published November 2, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.14%, the 3rd percentile. Fixed in quickjs-ng 0.16.2-1.

References

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