# CVE-2026-21636: Node.js: Improper Access Control

CVE-2026-21636 is fixed in Node.js on 1 platform by Node.js 25.3.0 (version 25.3.0), released January 12, 2026. It is not reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2026-21636
- Priority: Urgent
- CVSS: 10.0
- EPSS: 0.0087
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jan 20, 2026
- Weakness: CWE-284: Improper Access Control
- Vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-21636

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Windows apps | Node.js | 25.3.0 | [Node.js 25.3.0](https://patchblox.com/security/data/fix/windows-app/openjs.nodejs-25.3.0.md) | Jan 12, 2026 |

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Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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