High · CVSS 8.7CVE-2026-110869

Nodemailer 3.0.0 before 10.0.13 ReDoS via SMTP AUTH Mechanism Detection RegexesCVE-2026-110869

Answer in brief

CVE-2026-110869 records a High severity (CVSS 8.7) vulnerability in Nodemailer 3.0.0 before 10.0.13 ReDoS via SMTP AUTH Mechanism Detection Regexes. The current sources do not mark it as known exploited. The current feed maps nodemailer/nodemailer (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 14, 2026Updated Oct 14, 2026Source checked Oct 15, 2026First seen by HOL Oct 14, 2026Material review Oct 14, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.7
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 8.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps nodemailer/nodemailer (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
nodemailer/nodemailergeneric	>=3.0.0 <10.0.13	10.0.13

Recommended response

Check inventory. Check lockfiles and deployed manifests for nodemailer/nodemailer.
Review the reported fix. Update nodemailer/nodemailer to 10.0.13 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Oct 14, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 14, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 14, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.