Is CVE-2026-110869 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-110869 being exploited in the wild.

How severe is CVE-2026-110869?

High severity, with a CVSS score of 7.5, published 14 October 2026.

Which products and versions are affected?

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

Is there a fix for CVE-2026-110869?

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-2026-110869 attacked?

It is attacked over the network.

Am I affected by CVE-2026-110869?

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-2026-110869: Nodemailer regular expression denial of service in SMTP AUTH detection

CVE-2026-110869 · Severity: high · CVSS 7.5 · Published 2026-10-14

Nodemailer is a Node.js library that sends emails via SMTP servers. Versions 3.0.0 through 10.0.12 contain a flaw in how they parse SMTP server responses during the authentication handshake. An attacker controlling or intercepting the SMTP connection can craft a malicious response that causes the Node.js application to freeze for tens of seconds to hours, blocking all other work. No credentials are needed to mount the attack, making it a serious denial of service threat for any application sending emails through attacker-influenced servers.

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

Quick answers

Is CVE-2026-110869 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-110869 being exploited in the wild.
How severe is CVE-2026-110869?: High severity, with a CVSS score of 7.5, published 14 October 2026.
Which products and versions are affected?: Nodemailer 3.0.0 to 10.0.12; nodemailer (npm) SEMVER:introduced=3.0.0,fixed=10.0.13.
Is there a fix for CVE-2026-110869?: 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-2026-110869 attacked?: It is attacked over the network.
Am I affected by CVE-2026-110869?: 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

The vulnerability is a quadratic backtracking regex denial of service (ReDoS) in SMTPConnection._actionEHLO. Four overlapping regular expressions used to detect SASL AUTH mechanisms contain ambiguous whitespace-matching sub-patterns that cause the regex engine to try exponential combinations when a mechanism name is absent. A pre-authentication remote attacker can send an EHLO response with "250-AUTH" followed by a long whitespace run (up to 1 MB) and a non-matching token, causing the synchronous regex execution to block the Node.js event loop entirely.

Affected products

nodemailer Nodemailer 3.0.0 to 10.0.12

Identifiers

CVE-2026-110869
GHSA-4ffr-jq9g-5ffx

Timeline

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

References

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