Vulnerability 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.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Nodejs | Node.Js | >= 25.0.0, < 25.3.0 |
Related Weaknesses (CWE)
References
- https://nodejs.org/en/blog/vulnerability/december-2025-security-releasesVendor AdvisoryRelease Notes
FAQ
What is CVE-2026-21636?
CVE-2026-21636 is a vulnerability with a CVSS score of 10.0 (CRITICAL). 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 (...
How severe is CVE-2026-21636?
CVE-2026-21636 has been rated CRITICAL with a CVSS base score of 10.0/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-21636?
Check the references section above for vendor advisories and patch information. Affected products include: Nodejs Node.Js.