---
id: CVE-2026-100700
title: >-
  nodemailer before 10.0.6 contains a denial of service vulnerability in the
  addressparser free-text fallback regex pattern that exhibits quadratic
  backtracking behavior
summary: >-
  nodemailer before 10.0.6 contains a denial of service vulnerability in the
  addressparser free-text fallback regex pattern that exhibits quadratic
  backtracking behavior. Attackers can supply crafted email header values with
  long whitespac…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-407
  - CWE-1333
vendor: nodemailer
product: nodemailer
affected:
  - nodemailer < 10.0.6
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-2026-100700'
references:
  - url: >-
      https://github.com/nodemailer/nodemailer/security/advisories/GHSA-v53p-9fqp-m79j
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/nodemailer-before-10.0.6-denial-of-service-via-addressparser
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/nodemailer/nodemailer/security/advisories/GHSA-v53p-9fqp-m79j
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-100700.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-100700'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2541883'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-100700'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-100700'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
  - exploit-available
epss: 0.00337
epssPercentile: 0.26947
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-28T15:00:18.660649Z'
ingestedAt: '2026-09-26T13:33:20.900Z'
---

## Overview

nodemailer before 10.0.6 contains a denial of service vulnerability in the addressparser free-text fallback regex pattern that exhibits quadratic backtracking behavior. Attackers can supply crafted email header values with long whitespace-free runs to block the Node.js event loop for tens of seconds, causing service unavailability.

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Important · affected: Red Hat Developer Hub · no fix planned: Red Hat Developer Hub · updated 2026-10-22 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-100700.json)