Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| nodemailer | nodemailer | 3.0.0 – < 10.0.10 | 10.0.10 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | node-nodemailer | 10.0.10+~8.0.1-1 | — |
| Debian 13 | node-nodemailer | No fix yet | — |
| Debian 12 | node-nodemailer | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | node-nodemailer | No fix yet | — |
| Ubuntu 26.04 LTS | node-nodemailer | No fix yet | — |
| Ubuntu 24.04 LTS | node-nodemailer | No fix yet | — |
| Ubuntu 22.04 LTS | node-nodemailer | No fix yet | — |
| Ubuntu 20.04 LTS | node-nodemailer | No fix yet | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| npm | nodemailer | >= 3.0.0, < 10.0.10 | 10.0.10 | GHSA-39m8-27wv-hr27 |
References
- GitHub Security Advisory (GHSA-39m8-27wv-hr27) vendor-advisory
- VulnCheck Advisory: Nodemailer 3.0.0 before 10.0.10 Quadratic DKIM Header Unfolding Denial of Service third-party-advisory