CVE Vulnerabilities

CVE-2026-21636

Improper Access Control

Published: Jan 20, 2026 | Modified: Jan 30, 2026
CVSS 3.x
10
CRITICAL
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CVSS 2.x
RedHat/V2
RedHat/V3
5.8 MODERATE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
Ubuntu
MEDIUM
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A flaw in Node.jss 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.

Weakness

The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.

Affected Software

NameVendorStart VersionEnd Version
Node.jsNodejs25.0.0 (including)25.3.0 (excluding)
NodejsUbuntuplucky*

Extended Description

Access control involves the use of several protection mechanisms such as:

When any mechanism is not applied or otherwise fails, attackers can compromise the security of the product by gaining privileges, reading sensitive information, executing commands, evading detection, etc. There are two distinct behaviors that can introduce access control weaknesses:

Potential Mitigations

  • Compartmentalize the system to have “safe” areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
  • Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.

References