Memory leak in QuickJS-NG Atomics.store exhausts heap memory
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · Low
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-401.
Summary
QuickJS-NG before 0.16.0 contains a memory leak in js_atomics_store() in quickjs.c. The function fails to free a converted value when it returns a RangeError (CWE-401). An attacker running JavaScript can repeatedly call Atomics.store with a valueOf that detaches or shrinks the buffer, exhausting heap memory and causing a denial of service.
Written with Claude Haiku 5.5 from the sources below · 2026-11-03
Description from the CNA
QuickJS-NG before 0.16.0 contains a memory leak vulnerability in js_atomics_store() in quickjs.c that fails to free the converted value when returning a RangeError. Attackers running JavaScript can repeatedly call Atomics.store with a valueOf that detaches or shrinks the buffer to exhaust heap memory and cause denial of service.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| quickjs-ng | QuickJS-NG | before 0.16.0 | 0.16.0 | Patch available | CNA |
- QuickJS-NG Vendorquickjs-ng Affected before 0.16.0 Fixed in 0.16.0 Patch available CNA
Remediation
Upgrade QuickJS-NG to version 0.16.0 or later, which fixes the leak.
Written with Claude Haiku 5.5 from the sources below · 2026-11-03
- Fix · CNA QuickJS-NG (quickjs-ng) Fixed in 0.16.0
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
QuickJS-NG 0.16.0
3 records Highest priority Priority HIGH 1 HIGH, 2 LOW
Other records, highest priority first
- TI-2026-83831 Heap buffer overflow in QuickJS-NG TypedArray sort on 32-bit hostsPriority HIGH 69
- TI-2026-83830 Heap buffer overflow in QuickJS-NG via Proxy ownKeys enumerationPriority LOW 38
Vendor assessments
Timeline
- 2026-11-02 Threatist record created from CVE-2026-120440
- 2026-11-02 Alias added: GHSA-48fx-7fjq-qgg4
- 2026-11-02 CISA SSVC decision points changed
- 2026-11-02 Priority changed: MEDIUM → LOW
- 2026-11-03 Affected versions changed · Red Hat
- 2026-11-03 CVSS score added · Red Hat
References
More quickjs-ng vulnerabilities
- TI-2026-00603 quickjs-ng quickjs quickjs.c js_typed_array_constructor heap-based overflow CVSS 4.0MEDIUM 6.9
- TI-2025-29366 quickjs-ng through 0.9.0 has an incorrect size calculation in JS_ReadBigInt for a BigInt… CVSS 3.1HIGH 8.4
- TI-2026-83831 Heap buffer overflow in QuickJS-NG TypedArray sort on 32-bit hosts CVSS 4.0HIGH 8.3
- TI-2025-29365 Resource allocation without limits in QuickJS CVSS 3.1HIGH 7.8
- TI-2026-00873 quickjs-ng quickjs quickjs.c js_typed_array_constructor_ta heap-based overflow CVSS 4.0MEDIUM 5.3
- TI-2026-00872 quickjs-ng quickjs Atomics Ops quickjs.c use after free CVSS 4.0MEDIUM 5.3
Sources
- CVE-2026-120440 · CVE Program
- CVE-2026-120440 · NVD
- FIRST EPSS
- GHSA-48fx-7fjq-qgg4 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-120440 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences