CVE-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 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.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	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
https://github.com/nodemailer/nodemailer/security/advisories/GHSA-4ffr-jq9g-5ffx

Configurations

No configuration.

History

15 Oct 2026, 16:17

Type	Values Removed	Values Added
References	~~() https://github.com/nodemailer/nodemailer/security/advisories/GHSA-4ffr-jq9g-5ffx -~~	() https://github.com/nodemailer/nodemailer/security/advisories/GHSA-4ffr-jq9g-5ffx -

14 Oct 2026, 23:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-14 23:17

Updated : 2026-10-16 18:14

NVD link : CVE-2026-110869

Mitre link : CVE-2026-110869

CVE.ORG link : CVE-2026-110869

JSON object : View

Products Affected

No product.

CWE

CWE-1333

Inefficient Regular Expression Complexity

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