---
id: CVE-2026-100699
title: Nodemailer is a Node.js email-sending library
summary: >-
  Nodemailer is a Node.js email-sending library. In versions >= 9.1.0 and <
  10.0.9, the address parser (src/addressparser) mishandles addresses whose
  local-part is a quoted string and that are followed by RFC 5322 comments,
  allowing traili…
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N'
cwe:
  - CWE-20
  - CWE-1286
vendor: nodemailer
product: nodemailer
affected:
  - nodemailer >= 9.1.0 < 10.0.9
published: '2026-09-26'
updated: '2026-09-30'
sourceUpdated: '2026-09-30T16:32:17.940'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-100699'
references:
  - url: >-
      https://github.com/nodemailer/nodemailer/security/advisories/GHSA-g57g-f23g-4646
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/nodemailer-before-10.0.9-malformed-envelope-recipient-via-rfc-5322-comment
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/nodemailer/nodemailer/security/advisories/GHSA-g57g-f23g-4646
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-100699.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-100699'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2541880'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-100699'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-100699'
tags:
  - nvd
  - cve.org
  - exploit-available
  - csaf
  - vex
  - red-hat
epss: 0.00233
epssPercentile: 0.14164
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-28T17:42:55.592537Z'
ingestedAt: '2026-09-26T13:33:20.901Z'
---

## Overview

Nodemailer is a Node.js email-sending library. In versions >= 9.1.0 and < 10.0.9, the address parser (src/addressparser) mishandles addresses whose local-part is a quoted string and that are followed by RFC 5322 comments, allowing trailing comment-separated domain atoms to be retained in the normalized address. For example, the input "user"@example.com(x)evil.com is parsed to the address value 'user@example.com evil.com', which contains additional attacker-controlled domain text separated by a literal space. This parsed value is used without further strict recipient validation when the message envelope is built (envelope.to in src/mime-node), so a malformed/ambiguous recipient address can be accepted and placed in the SMTP envelope. Whether this results in delivery to an unintended recipient on real SMTP servers has not been confirmed. The issue is a variant of the RFC 5322 comment parsing problem addressed in GHSA-cc9r-2j5m-2m83, affecting the separate quoted-local-part code path. Version 10.0.9 contains a fix.

## 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, Red Hat Enterprise Linux 10, Self-service automation portal 2 · no fix planned: Red Hat Developer Hub, Red Hat Enterprise Linux 10, Self-service automation portal 2 · updated 2026-09-26 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-100699.json)