---
id: GHSA-wxxx-r42m-9rp8
title: >-
  Duplicate Advisory: Nodemailer: Quadratic (O(n^2)) DKIM header unfolding lets
  a large folded header cause remote denial of service during signing
summary: >-
  Duplicate Advisory: Nodemailer: Quadratic (O(n^2)) DKIM header unfolding lets
  a large folded header cause remote denial of service during signing
severity: high
cvss: 6.5
cwe:
  - CWE-400
vendor: nodemailer
product: nodemailer
ecosystem: npm
affected:
  - 'nodemailer >= 3.0.0, <= 10.0.9'
published: '2026-10-15'
updated: '2026-10-22'
sourceUpdated: '2026-10-22T16:06:04Z'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-wxxx-r42m-9rp8'
references:
  - url: >-
      https://github.com/nodemailer/nodemailer/security/advisories/GHSA-39m8-27wv-hr27
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-110871'
  - url: >-
      https://www.vulncheck.com/advisories/nodemailer-3.0.0-before-10.0.10-quadratic-dkim-header-unfolding-denial-of-service
  - url: 'https://github.com/advisories/GHSA-wxxx-r42m-9rp8'
tags:
  - ghsa
  - npm
ingestedAt: '2026-10-22T22:00:50.258Z'
---

## Overview

## Duplicate Advisory

This advisory has been withdrawn because it is a duplicate of GHSA-39m8-27wv-hr27. This link is maintained to preserve external references.

## Original Description
Nodemailer from 3.0.0 before 10.0.10 contains a denial of service vulnerability in MessageParser.parseHeaders that allows users to exhaust CPU through quadratic header unfolding. Attackers can supply large recipient lists or long headers that fold into tens of thousands of continuation lines, blocking the Node.js event loop during DKIM signing.

## Affected packages

- `nodemailer >= 3.0.0, <= 10.0.9`

## Remediation

Refer to the advisory for the patched release.