CVE-2026-100701

Nodemailer 5.0.0 through 10.0.1 TLS servername Cache Confusion

MEDIUM
5.9
CVSS Score
Published: September 26, 2026 at 01:23 PM UTC
Updated: September 30, 2026 at 04:32 PM UTC
1 product affected across 1 vendorNodemailer

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Severity
MEDIUM5.9
Exploit prediction
EPSS 0.1%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

5.0.0 ≤ v < 10.0.25.0.0
Vendor states this is fixed in 10.0.2 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.9MEDIUMVulnCheck
Attack Vector
NETWORK
Complexity
HIGH
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-295

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