---
id: CVE-2026-100701
title: >-
  Nodemailer versions 5.0.0 through 10.0.1 use a process-global DNS cache that
  is keyed only by the DNS host, while each cache entry also stores the
  caller-specific TLS servername
summary: >-
  Nodemailer versions 5.0.0 through 10.0.1 use a process-global DNS cache that
  is keyed only by the DNS host, while each cache entry also stores the
  caller-specific TLS servername. When two direct TLS/SMTPS transports (secure:
  true) resolv…
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N'
cwe:
  - CWE-295
vendor: nodemailer
product: nodemailer
affected:
  - nodemailer >= 5.0.0 < 10.0.2
published: '2026-09-26'
updated: '2026-09-26'
sourceUpdated: '2026-09-26T14:16:55.143'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-100701'
references:
  - url: >-
      https://github.com/nodemailer/nodemailer/security/advisories/GHSA-6vj9-mwq6-2f5v
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/nodemailer-5.0.0-through-10.0.1-tls-servername-cache-confusion
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-26T13:33:20.901Z'
---

## Overview

Nodemailer versions 5.0.0 through 10.0.1 use a process-global DNS cache that is keyed only by the DNS host, while each cache entry also stores the caller-specific TLS servername. When two direct TLS/SMTPS transports (secure: true) resolve the same non-IP host with different tls.servername values, the first transport's servername is returned on the cache hit and overwrites the second transport's explicitly configured value, so Nodemailer sends the wrong SNI value and validates the peer certificate against the wrong identity. In multi-tenant services or SNI-routed SMTP gateways, an attacker who can prime the cache can cause a victim transport to connect to the attacker's TLS virtual host and accept the attacker's certificate even with rejectUnauthorized: true, disclosing the victim's SMTP credentials. Fixed in 10.0.2.

## Remediation

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