CVE-2026-110871

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.

CVSS 4.0

7.1CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS 3.1

6.5CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS

0.4% chance of exploitation in the next 30 days; higher than 31% of CVEs (scores of 2026-10-25)

CWE

CWE-400

Published

2026-10-14

Modified

2026-10-20

Record from

the NVD, synced 2026-10-21

Packages (OSV)

References

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

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