---
id: CVE-2026-82854
title: >-
  Nodemailer before 8.0.4 is vulnerable to SMTP command injection through the
  unsanitized envelope.size parameter
summary: >-
  Nodemailer before 8.0.4 is vulnerable to SMTP command injection through the
  unsanitized envelope.size parameter. When an application passes a custom
  envelope object with a size property containing CRLF characters to sendMail(),
  the value…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-93
published: '2026-08-31'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T15:48:28.757'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-82854'
references:
  - url: >-
      https://github.com/nodemailer/nodemailer/security/advisories/GHSA-c7w3-x93f-qmm8
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/nodemailer-before-8.0.3-smtp-command-injection-via-envelope-size
    label: disclosure@vulncheck.com
tags:
  - nvd
epss: 0.01975
epssPercentile: 0.79611
ingestedAt: '2026-09-10T15:53:17.039Z'
---

## Overview

Nodemailer before 8.0.4 is vulnerable to SMTP command injection through the unsanitized envelope.size parameter. When an application passes a custom envelope object with a size property containing CRLF characters to sendMail(), the value is concatenated into the SMTP MAIL FROM command (as SIZE=...) without sanitization, allowing injection of arbitrary SMTP commands such as RCPT TO to silently add attacker-controlled recipients. Exploitation requires the application to expose the envelope size to attacker-controlled input, as Nodemailer does not include size in the default auto-constructed envelope.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.