CVE-2026-110871

MEDIUM 6.5

Nodemailer 3.0.0 before 10.0.10 Quadratic DKIM Header Unfolding Denial of Service

CVSS Score

6.5

EPSS Score

0.0%

EPSS Percentile

0th

Nodemailer from 3.0.0 before 10.0.10 contains a denial of service vulnerability in MessageParser.parseHeaders that allows users to exhaust CPU through quadratic header unfolding. Attackers can supply large recipient lists or long headers that fold into tens of thousands of continuation lines, blocking the Node.js event loop during DKIM signing.

CWE	CWE-400
Vendor	nodemailer
Product	nodemailer
Published	Oct 14, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Affected Versions

nodemailer / nodemailer

3.0.0 < 10.0.10

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/nodemailer/nodemailer/security/advisories/GHSA-39m8-27wv-hr27 vulncheck.com: https://www.vulncheck.com/advisories/nodemailer-3.0.0-before-10.0.10-quadratic-dkim-header-unfolding-denial-of-service

Credits

🔍 manus-pi 🔍 manus-use