CVE-2026-92596: Nodemailer before 9.1.0 Denial of Service via addressparser

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-16 · updated 2026-09-22
Weakness: CWE-400

Description

Nodemailer before 9.1.0 contains a quadratic time complexity vulnerability in the addressparser component that allows remote attackers to cause denial of service by supplying a crafted comma-separated address list. Attackers can send a single email with a large number of addresses to block the Node.js event loop for extended periods, consuming 100% CPU and freezing the process.

Affected products

nodemailer: before 9.1.0 — fixed in 9.1.0

How to fix

Upgrade to a fixed version: nodemailer 9.1.0. Check the vendor advisory for mitigations.

References

https://github.com/nodemailer/nodemailer/commit/34da642
https://github.com/nodemailer/nodemailer/commit/7cc38af
https://github.com/nodemailer/nodemailer/commit/83b8c48
https://github.com/nodemailer/nodemailer/commit/9116da9
https://github.com/nodemailer/nodemailer/security/advisories/GHSA-2x7j-588g-ccc2
https://www.vulncheck.com/advisories/nodemailer-before-9.1.0-denial-of-service-via-addressparser
https://github.com/nodemailer/nodemailer/security/advisories/GHSA-2x7j-588g-ccc2

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