How severe is CVE-2026-21636?

CVE-2026-21636 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-21636 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-21636?

CVE-2026-21636 affects Nodejs Node.js. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-21636?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-21636 have an EU (EUVD) identifier?

Yes. CVE-2026-21636 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-3334.

When was CVE-2026-21636 published?

CVE-2026-21636 was published on 2026-01-20 and last updated on 2026-06-17.

CVE-2026-21636

CVE-2026-21636 is a critical-severity vulnerability in Nodejs Node.js with a CVSS 3.x base score of 10.0. 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-284.

Key facts

Severity: Critical (CVSS 3.x base score 10.0)
EPSS exploit prediction: 1% (50th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-3334
Weakness: CWE-284
Affected product: Nodejs Node.js
Published: 2026-01-20
Last modified: 2026-06-17

Description

A flaw in Node.js's permission model allows Unix Domain Socket (UDS) connections to bypass network restrictions when `--permission` is enabled. Even without `--allow-net`, attacker-controlled inputs (such as URLs or socketPath options) can connect to arbitrary local sockets via net, tls, or undici/fetch. This breaks the intended security boundary of the permission model and enables access to privileged local services, potentially leading to privilege escalation, data exposure, or local code execution. * The issue affects users of the Node.js permission model on version v25. In the moment of this vulnerability, network permissions (`--allow-net`) are still in the experimental phase.

Frequently asked questions

What is CVE-2026-21636?: A flaw in Node.js's permission model allows Unix Domain Socket (UDS) connections to bypass network restrictions when `--permission` is enabled. Even without `--allow-net`, attacker-controlled inputs (such as URLs or socketPath options) can connect to arbitrary local sockets via net, tls, or undici/fetch. This breaks the intended security boundary of the permission model and enables access to privileged local services, potentially leading to privilege escalation, data exposure, or local code execution. * The issue affects users of the Node.js permission model on version v25. In the moment of this vulnerability, network permissions (`--allow-net`) are still in the experimental phase.
How severe is CVE-2026-21636?: CVE-2026-21636 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-21636 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-21636?: CVE-2026-21636 affects Nodejs Node.js. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-21636?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-21636 have an EU (EUVD) identifier?: Yes. CVE-2026-21636 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-3334.
When was CVE-2026-21636 published?: CVE-2026-21636 was published on 2026-01-20 and last updated on 2026-06-17.

References

https://nodejs.org/en/blog/vulnerability/december-2025-security-releases

Affected products (1)

cpe:2.3:a:nodejs:node.js:*:*:*:*:-:*:*:*

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