Is CVE-2026-110870 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-110870 being exploited in the wild.

How severe is CVE-2026-110870?

Medium severity, with a CVSS score of 5.3, published 14 October 2026.

Which products and versions are affected?

Nodemailer 3.0.0 through 10.0.12; nodemailer (npm) SEMVER:introduced=3.0.0,fixed=10.0.13.

Is there a fix for CVE-2026-110870?

Yes. nodemailer (npm): upgrade to 10.0.13 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-110870 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-110870?

Check whether you run Nodemailer or nodemailer (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-110870: Nodemailer improper input validation in address parser

CVE-2026-110870 · Severity: medium · CVSS 5.3 · Published 2026-10-14

Nodemailer is a widely-used Node.js email library that processes and validates recipient email addresses. The library fails to strip RFC 5322 comments from email addresses written in angle-bracket format (like "Name <user@domain.com(comment)>"), allowing attackers to inject malformed addresses that bypass email validation rules and cause delivery failures or allow-list bypasses. This could enable spammers or attackers to circumvent security controls designed to prevent emails from reaching certain domains.

Technologies: Nodemailer, nodemailer (npm). Vendors: Nodemailer, npm.

Quick answers

Is CVE-2026-110870 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-110870 being exploited in the wild.
How severe is CVE-2026-110870?: Medium severity, with a CVSS score of 5.3, published 14 October 2026.
Which products and versions are affected?: Nodemailer 3.0.0 through 10.0.12; nodemailer (npm) SEMVER:introduced=3.0.0,fixed=10.0.13.
Is there a fix for CVE-2026-110870?: Yes. nodemailer (npm): upgrade to 10.0.13 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-110870 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-110870?: Check whether you run Nodemailer or nodemailer (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

nodemailer (npm): upgrade to 10.0.13 or later
```
npm install nodemailer@10.0.13
```

Technical details

Nodemailer's address parser tokenizer does not recognize RFC 5322 comments (parenthesized text) when they appear inside angle-bracket addresses due to a single-slot operator stack that gates comment recognition. When parsing "user@domain.com(x)evil.com" in angle brackets, the comment is treated as literal text and passed through to SMTP RCPT TO commands verbatim, causing RFC 5321 syntax violations that conformant SMTP servers reject. The vulnerability affects versions 3.0.0 through 10.0.12 and is fixed by properly recognizing and stripping comments in all parsing contexts.

Affected products

NodeMailer Nodemailer 3.0.0 through 10.0.12

Identifiers

CVE-2026-110870
GHSA-g73g-hqqh-jr95

Timeline

2026-09-30: disclosed
2026-10-14: advisory

References

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