CVE-2026-21636

Updated on 20 Jan 2026

Severity

10.0 Critical severity

Details

CVSS score
10.0
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Overview

About vulnerability

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.

Details

Affected packages:
alt-nodejs16 @ 16 (+7 more)