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CVE-2026-3979· NVD / CVE Program· CNA VulDB

quickjs-ng quickjs quickjs.c js_iterator_concat_return use after free

A flaw has been found in quickjs-ng quickjs up to 0.12.1. This affects the function js_iterator_concat_return of the file quickjs.c. This manipulation causes use after free. The attack requires local access. The exploit has been published and may be used. Patch name: daab4ad4bae4ef071ed0294618d6244e92def4cd. Applying a patch is the recommended action to fix this issue.

LowCVSS 1.9 · v4.0—No exploit No fix recorded
Published
Mar 12, 2026
Updated
Jun 17, 2026
EPSS
0.2% · 5th percentile
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Report tools

JSON

Action score

7

Monitor

Low priority for now.

CVSS
7 / 40 · 1.9 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · VulDB
4.8
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

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Affected systems

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Versions reported by the vendor

Affected version ranges reported by the assigning authority (VulDB). Independent of NVD's CPE analysis and usually ahead of it.

  • quickjs-ng quickjs

    • 0.12.0, 0.12.1affected

Same product

quickjs-ng: all records

Other highest-scoring records for the same primary product.

  • CVE-2025-46688quickjs-ng through 0.9.0 has an incorrect size calculation in JS_ReadBigInt for a BigInt, leading to a heap-based buffer overflow.
    33Monitor
  • CVE-2025-46687quickjs-ng through 0.9.0 has a missing length check in JS_ReadString for a string, leading to a heap-based buffer overflow.
    31Monitor
  • CVE-2026-0821quickjs-ng quickjs quickjs.c js_typed_array_constructor heap-based overflow
    22Monitor
  • CVE-2024-13903quickjs-ng QuickJS qjs quickjs.c JS_GetRuntime stack-based overflow
    21Monitor
  • CVE-2026-1145quickjs-ng quickjs quickjs.c js_typed_array_constructor_ta heap-based overflow
    8Monitor
  • CVE-2026-1144quickjs-ng quickjs Atomics Ops quickjs.c use after free
    8Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-082161 days apartquickjs-ng quickjs quickjs.c js_typed_array_constructor heap-based overflow
    22Monitor
  • CVE-2024-13903356 days apartquickjs-ng QuickJS qjs quickjs.c JS_GetRuntime stack-based overflow
    21Monitor
  • CVE-2026-114452 days apartquickjs-ng quickjs Atomics Ops quickjs.c use after free
    8Monitor
  • CVE-2026-114552 days apartquickjs-ng quickjs quickjs.c js_typed_array_constructor_ta heap-based overflow
    8Monitor
  • CVE-2026-082261 days apartquickjs-ng quickjs quickjs.c js_typed_array_sort heap-based overflow
    8Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

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Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
X

Weakness class (CWE)

CWE-119 · Improper Restriction of Operations within the Bounds of a Memory Buffer

CVSS vector

CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

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Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records