A flaw in Node.js TLS hostname verification allows a certificate without a matching IP address SAN to authenticate a connection to an IPv4 address when the host is written with non-ASCII characters, such as fullwidth digits (`１２７.0.0.1`).

`tls.checkServerIdentity()` did not recognize such hosts as IP addresses, even though they normalize and resolve to a regular IPv4 address, and matched them against the certificate DNS names and Common Name instead. A certificate containing `DNS:127.0.0.1` or `DNS:*.0.0.1` could therefore be accepted for an IP endpoint it was not issued for. This is a regression introduced after the fix for CVE-2026-48618.

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

A flaw in Node.js TLS hostname verification allows a certificate without a matching IP address SAN to authenticate a connection to an IPv4 address when the host is written with non-ASCII characters, such as fullwidth digits (`１２７.0.0.1`).

`tls.checkServerIdentity()` did not recognize such hosts as IP addresses, even though they normalize and resolve to a regular IPv4 address, and matched them against the certificate DNS names and Common Name instead. A certificate containing `DNS:127.0.0.1` or `DNS:*.0.0.1` could therefore be accepted for an IP endpoint it was not issued for. This is a regression introduced after the fix for CVE-2026-48618.

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

corepack24-24.22.1-1.1 on GA media

Affected: Ubuntu:Pro:14.04:LTS: nodejs, Ubuntu:Pro:16.04:LTS: nodejs, Ubuntu:Pro:18.04:LTS: nodejs, Ubuntu:Pro:20.04:LTS: nodejs, Ubuntu:Pro:22.04:LTS: nodejs, Ubuntu:24.04:LTS: nodejs, Ubuntu:26.10: nodejs, Ubuntu:26.04:LTS: nodejs

[Unknown description]