Vulnerability · Published Aug 31, 2026 · Assigned by VulnCheck
CVE-2026-82854Nodemailer before 8.0.4 SMTP Command Injection via envelope.size
Critical 9.8
In plain English
A critical-severity security flaw in nodemailer from nodemailer. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 2.0% (higher than 81% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | node-nodemailer | no fix listed | DEBIAN-CVE-2026-82854 |
| Debian:13 | node-nodemailer | no fix listed | DEBIAN-CVE-2026-82854 |
| Debian:14 | node-nodemailer | 8.0.4+~7.0.11-1 | DEBIAN-CVE-2026-82854 |
| Ubuntu:22.04:LTS | node-nodemailer | no fix listed | UBUNTU-CVE-2026-82854 |
| Ubuntu:24.04:LTS | node-nodemailer | no fix listed | UBUNTU-CVE-2026-82854 |
| npm | nodemailer | 8.0.4 | GHSA-c7w3-x93f-qmm8 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| nodemailer | nodemailer | 0 – before 8.0.4 |
Weakness: CWE-93 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- GitHub Security Advisory (GHSA-c7w3-x93f-qmm8) vendor-advisory
- VulnCheck Advisory: Nodemailer before 8.0.4 SMTP Command Injection via envelope.size third-party-advisory