CVE-2026-82854 Nodemailer before 8.0.4 SMTP Command Injection via envelope.size
Attackers can inject SMTP commands via unsanitized envelope size, potentially adding unauthorized recipients if applications expose this parameter.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-82854?
CVE-2026-82854 is a critical command injection vulnerability in nodemailer, published on 31 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-93
Which versions are affected by CVE-2026-82854?
2 open source packages ship an affected version, including nodemailer.
| Package | Affected | Fixed in |
|---|---|---|
nodemailer npm | All versions | 8.0.4 |
nodemailer npm | All versions | 8.0.4 |
How do I fix CVE-2026-82854?
Upgrade nodemailer to 8.0.4 or later.
Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.
Is CVE-2026-82854 being exploited?
There is no known exploitation of CVE-2026-82854 in the wild and no public exploit code.
Sources
Also known as CLEANSTART-2026-ME00447, DEBIAN-CVE-2026-82854, ECHO-25c2-edb1-76f4, GHSA-2x76-7hhq-pgvw, GHSA-c7w3-x93f-qmm8, MINI-6hmq-w944-cv5x and 16 more.