Description
Nodemailer before 9.1.0 fails to apply UTS-46 normalization when encoding international domain names, causing the domain resolver to compute a different Punycode A-label than standards-compliant parsers. Attackers can craft recipient addresses with invisible characters or compatibility mappings that pass domain allow-list checks but are delivered to attacker-controlled domains via SMTP.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| nodemailer | nodemailer | < 9.1.0 | 9.1.0 |
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 | 10.0.0+~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 | 9.1.0 | GHSA-wmmp-3585-3rmp |
Advisories 1
- WID-SEC-2026-3621 IBM App Connect Enterprise: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 9, 2026
References
- GitHub Security Advisory (GHSA-wmmp-3585-3rmp) vendor-advisory
- Patch Commit patch
- Patch Commit patch
- VulnCheck Advisory: Nodemailer before 9.1.0 IDN/Punycode Domain Allow-list Bypass third-party-advisory