CVE-2026-3979
CVE-2026-3979 is a medium-severity vulnerability with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-119.
Key facts
- Severity: Medium (CVSS 3.x base score 5.3)
- CVSS v2: 4.3
- CVSS v4: 1.9
- EPSS exploit prediction: 0% (2nd percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-11519
- Weakness: CWE-119
- Published:
- Last modified:
Description
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.
Frequently asked questions
- What is CVE-2026-3979?
- 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.
- How severe is CVE-2026-3979?
- CVE-2026-3979 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
- Is CVE-2026-3979 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (2nd percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-3979?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2026-3979 have an EU (EUVD) identifier?
- Yes. CVE-2026-3979 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-11519.
- When was CVE-2026-3979 published?
- CVE-2026-3979 was published on 2026-03-12 and last updated on 2026-06-17.
References
- https://github.com/quickjs-ng/quickjs/
- https://github.com/quickjs-ng/quickjs/commit/daab4ad4bae4ef071ed0294618d6244e92def4cd
- https://github.com/quickjs-ng/quickjs/issues/1368
- https://github.com/quickjs-ng/quickjs/issues/1368#issue-4004680962
- https://github.com/quickjs-ng/quickjs/pull/1370
- https://vuldb.com/?ctiid.350414
- https://vuldb.com/?id.350414
- https://vuldb.com/?submit.769600
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