CVE-2026-110870 Nodemailer before 10.0.13 Improper Input Validation via Angle-Bracket Address Comments
Attackers can bypass domain allow-lists or cause delivery failures in Nodemailer by injecting RFC 5322 comments into email addresses.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-110870?
CVE-2026-110870 is a medium-severity 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 10.0.13 contains an improper input validation vulnerability in its address parser that fails to strip RFC 5322 comments inside angle-bracket addresses. Attackers can supply recipients like a display name with a parenthesized comment in the domain, so illegal characters reach envelope.to and RCPT TO, causing rejected delivery or parser interpretation conflicts that bypass domain allow-lists.
Weakness: CWE-20
Which versions are affected by CVE-2026-110870?
2 open source packages ship an affected version, including nodemailer.
| Package | Affected | Fixed in |
|---|---|---|
nodemailer npm | From 3.0.0 | 10.0.13 |
nodemailer npm | From 3.0.0 | 10.0.13 |
How do I fix CVE-2026-110870?
Upgrade nodemailer to 10.0.13 or later.
Is CVE-2026-110870 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-110870 exists.
Sources
Also known as CLSA-2026-1793180903, CLSA-2026-1793183905, CLSA-2026-1793187944, CLSA-2026-1793207112, CLSA-2026-1793209433, CLSA-2026-1793215120 and 6 more.