Description
Nodemailer before 9.1.0 contains a quadratic time complexity vulnerability in the addressparser component that allows remote attackers to cause denial of service by supplying a crafted comma-separated address list. Attackers can send a single email with a large number of addresses to block the Node.js event loop for extended periods, consuming 100% CPU and freezing the process.
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-2x7j-588g-ccc2 |
Advisories 1
- WID-SEC-2026-3621 IBM App Connect Enterprise: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 9, 2026
References
- GitHub Security Advisory (GHSA-2x7j-588g-ccc2) vendor-advisory
- Patch Commit patch
- Patch Commit patch
- Patch Commit patch
- Patch Commit patch
- VulnCheck Advisory: Nodemailer before 9.1.0 Denial of Service via addressparser third-party-advisory