Description
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.
Published: 2026-09-26
Score: 6 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Advisories

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History

Sat, 26 Sep 2026 13:30:00 +0000

Type Values Removed Values Added
Description 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.
Title Nodemailer 5.0.0 through 10.0.1 TLS servername Cache Confusion
First Time appeared Nodemailer
Nodemailer nodemailer
Weaknesses CWE-295
CPEs cpe:2.3:a:nodemailer:nodemailer:*:*:*:*:*:*:*:*
Vendors & Products Nodemailer
Nodemailer nodemailer
References
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N'}

cvssV4_0

{'score': 6, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N'}


Subscriptions

Nodemailer Nodemailer
cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-09-26T13:23:57.215Z

Reserved: 2026-09-26T02:39:50.973Z

Link: CVE-2026-100701

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-26T14:16:55.143

Modified: 2026-09-26T14:16:55.143

Link: CVE-2026-100701

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-26T17:00:15Z

Weaknesses
  • CWE-295

    Improper Certificate Validation