CVE-2026-38728 smtp-server's command parser memory exhaustion denial-of-service
A remote attacker can cause a denial of service in Nodemailer smtp_server via the SMTPStream._write component.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-38728?
CVE-2026-38728 is a high-severity denial of service vulnerability in n/a, published on 15 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
An issue in Nodemailer smtp_server before v.3.18.3 allows a remote attacker to cause a denial of service via the SMTPStream._write, lib/smtp-stream.js components
Weakness: CWE-400
Which versions are affected by CVE-2026-38728?
2 open source packages ship an affected version, including smtp-server.
| Package | Affected | Fixed in |
|---|---|---|
smtp-server npm | All versions | 3.18.3 |
smtp-server npm | All versions | 3.18.3 |
How do I fix CVE-2026-38728?
Upgrade smtp-server to 3.18.3 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-38728 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-38728 exists.
Sources
Also known as GHSA-fv2f-rw9f-v9cm.