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**.
History

Mon, 26 Oct 2026 12:15:00 +0000

Type Values Removed Values Added
Title Non‑Canonical IPv4 Spelling Allows TLS Hostname Verification Bypass in Node.js nodejs: nodejs: Authentication bypass via non-canonical IPv4 hostname verification
References
Metrics threat_severity

None

cvssV3_1

{'score': 6.7, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:L'}

threat_severity

Moderate


Fri, 23 Oct 2026 22:00:00 +0000

Type Values Removed Values Added
First Time appeared Nodejs
Nodejs nodejs
Vendors & Products Nodejs
Nodejs nodejs

Fri, 23 Oct 2026 17:45:00 +0000

Type Values Removed Values Added
Title Non‑Canonical IPv4 Spelling Allows TLS Hostname Verification Bypass in Node.js

Fri, 23 Oct 2026 16:30:00 +0000

Type Values Removed Values Added
Description 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**.
Weaknesses CWE-295
References
Metrics cvssV3_0

{'score': 6.7, 'vector': 'CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:L'}


cve-icon MITRE

Status: PUBLISHED

Assigner: hackerone

Published: 2026-10-23T16:15:05.783Z

Updated: 2026-10-23T16:15:05.783Z

Reserved: 2026-10-06T15:00:00.655Z

Link: CVE-2026-106072

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-10-23T17:17:20.203

Modified: 2026-10-23T19:42:24.553

Link: CVE-2026-106072

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-10-23T16:15:05Z

Links: CVE-2026-106072 - Bugzilla