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CVE-2026-21636

CRITICALCVSS 10/10EPSS 0.66%

Last modified

CVE-2026-21636 is a critical-severity vulnerability rated 10/10 on the CVSS scale. 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. EPSS estimates a 0.66% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
10/10

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

CVSS 3.0
5.8/10

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N

EPSS Probability
0.66%

47.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
NodejsNode.Js>= 25.0.0, < 25.3.0

References

Timeline

Published
Last Modified
Status
Analyzed

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 score of 10/10 (CRITICAL severity). The EPSS model estimates a 0.66% probability of exploitation in the next 30 days.
How do I fix CVE-2026-21636?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-21636?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST