Vulnerability 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.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://github.com/nodemailer/nodemailer/security/advisories/GHSA-6vj9-mwq6-2f5v
- https://www.vulncheck.com/advisories/nodemailer-5.0.0-through-10.0.1-tls-servern
FAQ
What is CVE-2026-100701?
CVE-2026-100701 is a vulnerability with a CVSS score of 5.9 (MEDIUM). 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/S...
How severe is CVE-2026-100701?
CVE-2026-100701 has been rated MEDIUM with a CVSS base score of 5.9/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-100701?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.