CVE-2026-21636: nodejs node Improper Access Control

Vulnerability summary

CVE-2026-21636 is a critical (CVSS 10.0) Improper Access Control vulnerability in nodejs node. EPSS estimates a 0.87% chance of exploitation in the next 30 days, higher than 58.1% of scored vulnerabilities.

Timeline

1. 20-01-2026
   PublishedVulnerability first disclosed.
2. 21-01-2026
   Last modifiedVulnerability information updated.

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.

• CWE-284Improper Access ControlThe product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.