---
id: "CVE-2026-121425"
kind: "vulnerability"
aliases: ["CVE-2026-121425"]
title: "Nodemailer: address parser flaw lets crafted emails bypass recipient allow lists"
severity: "high"
cvss: 8.3
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["email", "node.js", "nodemailer", "package"]
not_affected_if: ["hardcoded-recipients", "no-user-supplied-addresses"]
published_at: "2026-11-03T15:17:33+00:00"
first_seen_at: "2026-11-03T15:21:59+00:00"
updated_at: "2026-11-03T15:22:42+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-121425", "first_seen_at": "2026-11-03T15:21:59+00:00"}]
---

# Nodemailer: address parser flaw lets crafted emails bypass recipient allow lists

Nodemailer's addressparser ends RFC 5322 group addresses early at a semicolon inside quoted names or comments. An attacker can submit crafted addresses that pass validation and redirect mail to recipients of their choosing, bypassing allow lists.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed version with `npm ls nodemailer` and compare it to the fixed range.
- Search your lockfiles and dependency trees for `nodemailer` below `10.1.4`.
- Review any code that validates recipient addresses and relies on Nodemailer's parsing.

## Fix

- Nodemailer: upgrade to `10.1.4` or later (affected range is `3.0.0` up to but not including `10.1.4`).

## Timeline

- 2026-11-03T15:21:59+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-121425

## Documents

- [advisory] Vendor advisory: github.com https://github.com/nodemailer/nodemailer/security/advisories/GHSA-m943-m63m-w62w
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/nodemailer-3.0.0-before-10.1.4-recipient-injection-via-addressparser-group-parsing

## From the sources

Nodemailer from 3.0.0 before 10.1.4 contains a parsing flaw in addressparser that ends an RFC 5322 group at a semicolon inside quoted display names or comments. Attackers can submit crafted group addresses that conformant validators approve, redirecting mail to attacker-chosen recipients and bypassing recipient allow lists.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_