---
id: CVE-2026-92598
title: >-
  Nodemailer before 9.1.0 fails to apply UTS-46 normalization when encoding
  international domain names, causing the domain resolver to compute a different
  Punycode A-label than standards-compliant parsers
summary: >-
  Nodemailer before 9.1.0 fails to apply UTS-46 normalization when encoding
  international domain names, causing the domain resolver to compute a different
  Punycode A-label than standards-compliant parsers. Attackers can craft
  recipient add…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N'
cwe:
  - CWE-436
  - CWE-289
vendor: nodemailer
product: nodemailer
affected:
  - nodemailer < 9.1.0
published: '2026-09-16'
updated: '2026-09-22'
sourceUpdated: '2026-09-22T20:25:55.870'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-92598'
references:
  - url: 'https://github.com/nodemailer/nodemailer/commit/259c32d'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/nodemailer/nodemailer/commit/b212ac4'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/nodemailer/nodemailer/security/advisories/GHSA-wmmp-3585-3rmp
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/nodemailer-before-9.1.0-idn-punycode-domain-allow-list-bypass
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/nodemailer/nodemailer/security/advisories/GHSA-wmmp-3585-3rmp
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-92598.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-92598'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-92598'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-92598'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2536089'
tags:
  - nvd
  - cve.org
  - exploit-available
  - csaf
  - vex
  - red-hat
epss: 0.00264
epssPercentile: 0.18605
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-17T14:40:05.615875Z'
ingestedAt: '2026-09-16T22:06:50.927Z'
---

## Overview

Nodemailer before 9.1.0 fails to apply UTS-46 normalization when encoding international domain names, causing the domain resolver to compute a different Punycode A-label than standards-compliant parsers. Attackers can craft recipient addresses with invisible characters or compatibility mappings that pass domain allow-list checks but are delivered to attacker-controlled domains via SMTP.

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Developer Hub, Self-service automation portal 2 · no fix planned: Red Hat Developer Hub, Self-service automation portal 2 · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-92598.json)