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.

How to fix CVE-2026-21636

To remediate CVE-2026-21636, upgrade the affected package to a fixed version below.

• —upgrade to 25.3.0 or later
• —upgrade to 25.3.0 or later

Is CVE-2026-21636 being exploited?

Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.

Affected packages (2)

• >= 25.0.0, < 25.3.0
• >= 25.0.0, < 25.3.0

CVSS scores

References (2)

• WEBnodejs.org/en/blog/vulnerability/december-2025-security-releases
• WEBnvd.nist.gov/vuln/detail/CVE-2026-21636