8.7
HIGH CVSS 4.0
CVE-2026-110869
Nodemailer 3.0.0 before 10.0.13 ReDoS via SMTP AUTH Mechanism Detection Regexes
Description

Nodemailer 3.0.0 before 10.0.13 has a regular expression denial of service in SMTPConnection._actionEHLO, whose four AUTH mechanism detection regexes contain overlapping whitespace sub-patterns that backtrack quadratically. A malicious or man-in-the-middle SMTP server can reply to EHLO with 250-AUTH, a long whitespace run and a non-matching token, blocking the Node.js event loop for tens of seconds to hours before authentication.

INFO

Published Date :

Oct. 14, 2026, 11:17 p.m.

Last Modified :

Oct. 14, 2026, 11:17 p.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-110869 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Nodemailer nodemailer
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 HIGH 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 3.1 HIGH MITRE-CVE
CVSS 3.1 HIGH [email protected]
CVSS 4.0 HIGH 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 4.0 HIGH [email protected]
Solution
Update Nodemailer to version 10.0.13 or later to fix denial of service vulnerability.
  • Update Nodemailer to version 10.0.13 or later.
  • Apply vendor-provided patches or updates.
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-110869.

URL Resource
https://github.com/nodemailer/nodemailer/security/advisories/GHSA-4ffr-jq9g-5ffx
https://www.vulncheck.com/advisories/nodemailer-3.0.0-before-10.0.13-redos-via-smtp-auth-mechanism-detection-regexes
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-110869 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-110869 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-110869 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-110869 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    Oct. 14, 2026

    Action Type Old Value New Value
    Added Description Nodemailer 3.0.0 before 10.0.13 has a regular expression denial of service in SMTPConnection._actionEHLO, whose four AUTH mechanism detection regexes contain overlapping whitespace sub-patterns that backtrack quadratically. A malicious or man-in-the-middle SMTP server can reply to EHLO with 250-AUTH, a long whitespace run and a non-matching token, blocking the Node.js event loop for tens of seconds to hours before authentication.
    Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
    Added CWE CWE-1333
    Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/110xxx/CVE-2026-110869.json">CVE-2026-110869</a>
    Added Reference https://github.com/nodemailer/nodemailer/security/advisories/GHSA-4ffr-jq9g-5ffx
    Added Reference https://www.vulncheck.com/advisories/nodemailer-3.0.0-before-10.0.13-redos-via-smtp-auth-mechanism-detection-regexes
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.