CVE-2026-21636: Nodejs Node.js broken access control (CVSS 10.0)

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.

CVSS 3.1 breakdown

Attack vectorNetwork

Attack complexityLow

Privileges requiredNone

User interactionNone

ScopeChanged

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Affected products

Nodejs Node.js≥ 25.0.0 < 25.3.0

Remediation

Fixed in

Nodejs Node.js≥ 25.3.0

Patch & vendor advisories

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

References

https://nodejs.org/en/blog/vulnerability/december-2025-security-releasesRelease NotesVendor Advisory

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

Frequently asked

Is CVE-2026-21636 being actively exploited?

CVE-2026-21636 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.88%.

How severe is CVE-2026-21636?

CVE-2026-21636 has a CVSS 3.1 base score of 10.0, rated critical. EPSS estimates a 0.88% probability of exploitation.

Which products are affected by CVE-2026-21636?

Affected products include Nodejs Node.js.

How do I fix CVE-2026-21636?

Upgrade affected software to a fixed version, for example Nodejs Node.js 25.3.0 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-21636 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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