CVE-2026-110872 Nodemailer 3.0.0 before 10.0.10 Denial of Service via SMTP Reply Parsing
A malicious SMTP server can cause a denial of service in Nodemailer by streaming continuation lines, blocking the event loop and exhausting memory.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-110872?
CVE-2026-110872 is a high-severity denial of service vulnerability in nodemailer, published on 14 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Nodemailer from 3.0.0 before 10.0.10 contains a quadratic complexity denial of service vulnerability in the SMTP client reply parser in SMTPConnection._onData and isPartialResponse. A malicious SMTP server or on-path attacker can stream continuation lines without a completion line before authentication, blocking the Node.js event loop and exhausting memory.
Weakness: CWE-400
Which versions are affected by CVE-2026-110872?
2 open source packages ship an affected version, including nodemailer.
| Package | Affected | Fixed in |
|---|---|---|
nodemailer npm | From 3.0.0 | 10.0.10 |
nodemailer npm | From 3.0.0 | 10.0.10 |
How do I fix CVE-2026-110872?
Upgrade nodemailer to 10.0.10 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-2026-110872 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-110872 exists.
Sources
Also known as CLSA-2026-1793102593, CLSA-2026-1793181005, CLSA-2026-1793183896, DEBIAN-CVE-2026-110872, ECHO-5c4c-bea4-f8fb, GHSA-37fc-hcrp-mmff and 2 more.