CVE-2026-90776
Received Received - Intake

Quadratic Time Complexity in Nodemailer Addressparser

Publication date: 2026-09-13

Last updated on: 2026-09-13

Assigner: VulnCheck

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.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-09-13
Last Modified
2026-09-13
Generated
2026-09-13
AI Q&A
2026-09-13
EPSS Evaluated
N/A
NVD
CVE-2026-90776
EUVD
EUVD-2026-77000

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
nodemailer nodemailer From 9.1.0 (inc) to 10.0.4 (inc)
nodemailer nodemailer From 9.1.0 (inc) to 10.0.5 (exc)

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-407 An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

This vulnerability is a denial-of-service issue in Nodemailer versions 9.1.0 through 10.0.4 caused by quadratic time complexity in the addressparser component. Attackers can craft malicious email headers with RFC 5322 comments (e.g., a@b(c)@b(c)@b(c)...) to consume excessive CPU resources and block the Node.js event loop for several seconds.

Detection Guidance

Monitor for unusually high CPU usage or event loop delays when processing email headers. Check Nodemailer version with 'npm list nodemailer' or 'npm ls nodemailer'. If using versions 9.1.0 through 10.0.4, the system is vulnerable.

Impact Analysis

This vulnerability can cause service disruptions by consuming excessive CPU and blocking the Node.js event loop. A single crafted email can stall a service parsing mail headers, potentially keeping the service down with just a few requests. It is exploitable remotely without authentication.

Compliance Impact

This vulnerability could impact compliance with GDPR and HIPAA by causing service disruptions due to denial-of-service conditions. Excessive CPU usage and blocked event loops may lead to unavailability of email processing systems, potentially violating availability requirements in these regulations.

Mitigation Strategies

Upgrade Nodemailer to version 10.0.5 or later using 'npm install nodemailer@latest'. If immediate upgrade isn't possible, implement rate limiting on email header parsing or block suspicious headers containing excessive comments.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-90776. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart