CVE-2026-106072: A flaw in Node.js TLS hostname verification allows a certificate with only a DNS SAN to authenticate an IP endpoint when the client connects using a non-canonical IPv4 spelling, such as `0177.0.0.1`, `0x7f.0.0.1`, `2130706433` or `127.1`.
`tls.checkServerIdentity()` did not classify these hosts as IP addresses, but normalized them to their canonical form and matched the result against the certificate DNS names. A certificate containing `DNS:127.0.0.1` and no `IP Address:127.0.0.1` SAN was therefore accepted, while the same certificate is correctly rejected for `127.0.0.1`. Exploitation requires a certificate with a numeric DNS SAN issued by a CA trusted by the client, and a platform resolver that accepts these spellings, such as glibc.
This vulnerability affects Node.js **26.x**, **24.x**, and **22.x**.
Overview
- Severity
- Medium (CVSS 6.7)
- CVSS Vector
- CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:L
- Exploit Status
- Not Exploited
- Patch Tuesday
- 2026-Oct
- Released
- 2026-10-25
- Last Updated
- 2026-10-26
- EPSS Score
- 0.55% (percentile: 45.7%)
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.