Nodemailer 5.0.0 through 10.0.1 TLS servername Cache Confusion (CVE-2026-100701) | HOL Guard CVE

Medium · CVSS 6.0CVE-2026-100701

Nodemailer 5.0.0 through 10.0.1 TLS servername Cache Confusion

Answer in brief

CVE-2026-100701 records a Medium severity (CVSS 6.0) vulnerability in Nodemailer 5.0.0 through 10.0.1 TLS servername Cache Confusion. The current sources do not mark it as known exploited. The current feed maps nodemailer/nodemailer (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 26, 2026Updated Sep 26, 2026Source checked Sep 26, 2026First seen by HOL Sep 26, 2026Material review Sep 26, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 6.0
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 6.0. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps nodemailer/nodemailer (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
nodemailer/nodemailergeneric	>=5.0.0 <10.0.2	10.0.2

Recommended response

Check inventory. Check lockfiles and deployed manifests for nodemailer/nodemailer.
Review the reported fix. Update nodemailer/nodemailer to 10.0.2 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 26, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 26, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 26, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.