Vulnerabilities

Vulnerability · CVE-2026-110869

Nodemailer 3.0.0 before 10.0.13 ReDoS via SMTP AUTH Mechanism Detection Regexes

Published Oct 14, 2026 · catalog updated Oct 15, 2026 · Nodemailer 3.0.0 before 10.0.13

Check if you run it

No confirmed exploitation is on record for CVE-2026-110869. EPSS is 0.30%. Act only if a listed version of Nodemailer 3.0.0 before 10.0.13 is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Nodemailer 3.0.0 before 10.0.13).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High8.7
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.30%
Remediation
Advisory link
Affected products
Debian:12 node-nodemailer · Debian:13 node-nodemailer · Debian:14 node-nodemailer · package maven · package npm · vendor nodemailer nodemailer

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • Debian:12 node-nodemailer10.0.0+~8.0.1-1, 10.0.10+~8.0.1-1, 10.0.10+~8.0.2-1
  • Debian:13 node-nodemailer10.0.0+~8.0.1-1, 10.0.10+~8.0.1-1, 10.0.10+~8.0.2-1
  • Debian:14 node-nodemailer0 → 10.0.13+~8.0.2-1
  • package mavenversion unspecified
  • package npmversion unspecified
  • vendor nodemailer nodemailerversion unspecified

How to fix CVE-2026-110869

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-110869. EPSS is 0.30%. Act only if a listed version of Nodemailer 3.0.0 before 10.0.13 is installed.

Which versions are affected?

Compare what you have installed with 10.0.0+~8.0.1-1, 10.0.10+~8.0.1-1, 10.0.10+~8.0.2-1, 0 → 10.0.13+~8.0.2-1. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-1333: Inefficient Regular Expression Complexity. EPSS 0.30%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 14, 2026 · NIST NVD

    Detected

    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 second

  2. Oct 15, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    node-nodemailer fixed in 10.0.13+~8.0.2-1

  3. Oct 15, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    node-nodemailer fixed in 10.0.13+~8.0.2-1

  4. Oct 15, 2026 · OpenSSF OSV / OSV Scanner

    Updated

    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 second

  5. Oct 15, 2026 · NIST NVD

    Updated

    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 second

Sources

  • CVE.orgVulnerability recordCVE-2026-110869

    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 t

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-110869

    30-day exploitation probability 0.3%

    first.org
  • NIST NVDVulnerability recordCVE-2026-110869

    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 t

    nvd.nist.gov
  • OpenSSF OSV / OSV ScannerPackage advisoryDEBIAN-CVE-2026-110869
    osv.dev
  • Snyk Vulnerability DatabasePackage advisorySNYK-JAVA-ORGWEBJARSNPM-20953007

    Regular Expression Denial of Service (ReDoS)

    security.snyk.io
  • Snyk Vulnerability DatabasePackage advisorySNYK-JS-NODEMAILER-20953006

    Regular Expression Denial of Service (ReDoS)

    security.snyk.io

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.