Vulnerability · Published Sep 13, 2026 · Assigned by VulnCheck

CVE-2026-90776Nodemailer 9.1.0 through 10.0.4 Denial of Service via Quadratic Address Parsing

High 7.5

In plain English

A high-severity security flaw in nodemailer from nodemailer. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 53% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.7%top 47.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

Nodemailer versions 9.1.0 through 10.0.4 contain a quadratic time complexity vulnerability in the addressparser component when parsing email addresses with RFC 5322 comments. Attackers can craft malicious email headers with comment-separated atoms to consume excessive CPU and block the Node.js event loop for several seconds, causing denial of service.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	node-nodemailer	no fix listed	DEBIAN-CVE-2026-90776
Debian:13	node-nodemailer	no fix listed	DEBIAN-CVE-2026-90776
Debian:14	node-nodemailer	10.0.10+~8.0.1-1	DEBIAN-CVE-2026-90776
Ubuntu:22.04:LTS	node-nodemailer	no fix listed	UBUNTU-CVE-2026-90776
Ubuntu:24.04:LTS	node-nodemailer	no fix listed	UBUNTU-CVE-2026-90776
Ubuntu:26.04:LTS	node-nodemailer	no fix listed	UBUNTU-CVE-2026-90776
Ubuntu:26.10	node-nodemailer	no fix listed	UBUNTU-CVE-2026-90776
npm	nodemailer	10.0.5	GHSA-prgh-xp8r-p3m5

Affected products (as reported)

Vendor	Product	Versions
nodemailer	nodemailer	9.1.0 – before 10.0.5

Weakness: CWE-407 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

GitHub Security Advisory (GHSA-prgh-xp8r-p3m5) vendor-advisory
Patch Commit patch
Vulnerable join check in addressparser at v10.0.4 technical-description
nodemailer v10.0.5 Release Notes release-notes
https://github.com/nodemailer/nodemailer product
VulnCheck Advisory: Nodemailer 9.1.0 through 10.0.4 Denial of Service via Quadratic Address Parsing third-party-advisory