CVE-2026-106069: 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**.
Overview
- Severity
- High (CVSS 7.4)
- CVSS Vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
- Exploit Status
- Not Exploited
- Patch Tuesday
- 2026-Oct
- Released
- 2026-10-25
- Last Updated
- 2026-10-26
- EPSS Score
- 0.27% (percentile: 19.8%)
Detection & Weaponization (1 sources)
Maturity: Exploit
- GitHub PoC: 1 repositories
Affected Products (1)
Open Source Software
- azl3 nodejs 24.21.0-1 on Azure Linux 3.0
Revision History
- 2026-10-25: Information published.
- 2026-10-26: Information published.