---
id: CVE-2026-106069
title: >-
  A flaw in Node.js TLS hostname verification can cause a server certificate to
  be validated against a different IP address than the one the client connected
  to, when the host is a non-canonical IPv4 literal with a leading zero, such as
  `0…
summary: >-
  A flaw in Node.js TLS hostname verification can cause a server certificate to
  be validated against a different IP address than the one the client connected
  to, when the host is a non-canonical IPv4 literal with a leading zero, such as
  `0…
severity: high
cvss: 7.4
cvssVector: 'CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N'
cvssSource: cna
cwe:
  - CWE-295
vendor: nodejs
product: node
affected:
  - node >= 22.23.3 <= 22.23.3
  - node >= 24.22.0 <= 24.22.0
  - node >= 26.12.0 <= 26.12.0
published: '2026-10-23'
updated: '2026-10-23'
sourceUpdated: '2026-10-23T16:15:05.850Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-106069'
references:
  - url: 'https://nodejs.org/en/blog/vulnerability/october-2026-security-releases'
tags:
  - cve.org
ingestedAt: '2026-10-23T16:31:11.319Z'
---

## Overview

A flaw in Node.js TLS hostname verification can cause a server certificate to be validated against a different IP address than the one the client connected to, when the host is a non-canonical IPv4 literal with a leading zero, such as `0127.0.0.1`.

`tls.checkServerIdentity()` normalizes the host following the WHATWG URL rules, which read a leading-zero octet as octal (`0127.0.0.1` becomes `87.0.0.1`), while the connection is made through the operating system resolver, which on some platforms such as macOS reads it as decimal (`127.0.0.1`). A server at the connected address can then be authenticated with a certificate issued for another IP address.

This vulnerability affects Node.js **26.x**, **24.x**, and **22.x**.

## Affected

- `node >= 22.23.3 <= 22.23.3`
- `node >= 24.22.0 <= 24.22.0`
- `node >= 26.12.0 <= 26.12.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.