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 products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| nodemailer | nodemailer | 9.1.0 – < 10.0.5 | 10.0.5 |
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 | >= 9.1.0, < 10.0.5 | 10.0.5 | GHSA-prgh-xp8r-p3m5 |
Advisories 1
- WID-SEC-2026-4410 IBM App Connect Enterprise: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 10, 2026
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