CVE-2026-82854: Nodemailer

Critical severity, CVSS 9.8. EPSS: 2% chance of exploitation in the next 30 days.

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 products

• Nodemailer Nodemailer: before 8.0.3 (fixed in 8.0.3)

Published 2026-08-31. Last modified 2026-10-08.