Nodemailer: Quadratic (O(n²)) time complexity in addressparser

Published September 8, 2026 GHSA-2x7j-588g-ccc2

Nodemailer: Quadratic (O(n²)) time complexity in addressparser allows remote denial of service via a crafted address list. Nodemailer's address parser (lib/addressparser/index.js) parses a list of comma‑separated addresses in quadratic time — O(n²) in the number of addresses.

Severity
HighCVSS 7.5
Fix
Fixed in 9.1.0Fix recorded 2 days ago
Affected versions
before 9.1.0
Affects
nodemailer

What to do

Run this in the application environment you want to check:

npm ls --all nodemailer

Update to 9.1.0 or later.

References