Nodemailer vulnerabilities

CVE-2026-110872 Medium · 5.9 CWE-400 Oct 14, 2026

Nodemailer 3.0.0 before 10.0.10 Denial of Service via SMTP Reply Parsing

Nodemailer from 3.0.0 before 10.0.10 contains a quadratic complexity denial of service vulnerability in the SMTP client reply parser in SMTPConnection._onData and isPartialResponse. A malicious SMTP server or on-path attacker can stream continuation lines without a completion line before authentication, blocking the Node.js event loop and exhausting memory.

CVE-2026-110871 Medium · 6.5 CWE-400 Oct 14, 2026

Nodemailer 3.0.0 before 10.0.10 Quadratic DKIM Header Unfolding Denial of Service

Nodemailer from 3.0.0 before 10.0.10 contains a denial of service vulnerability in MessageParser.parseHeaders that allows users to exhaust CPU through quadratic header unfolding. Attackers can supply large recipient lists or long headers that fold into tens of thousands of continuation lines, blocking the Node.js event loop during DKIM signing.

CVE-2026-110870 Medium · 5.3 CWE-20 Oct 14, 2026

Nodemailer before 10.0.13 Improper Input Validation via Angle-Bracket Address Comments

Nodemailer from 3.0.0 before 10.0.13 contains an improper input validation vulnerability in its address parser that fails to strip RFC 5322 comments inside angle-bracket addresses. Attackers can supply recipients like a display name with a parenthesized comment in the domain, so illegal characters reach envelope.to and RCPT TO, causing rejected delivery or parser interpretation conflicts that bypass domain allow-lists.

CVE-2026-110869 High · 7.5 CWE-1333 Oct 14, 2026

Nodemailer 3.0.0 before 10.0.13 ReDoS via SMTP AUTH Mechanism Detection Regexes

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.

CVE-2026-82854 Critical · 9.8 CWE-93 Aug 31, 2026

Nodemailer before 8.0.3 SMTP Command Injection via envelope.size

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.

CVE-2026-3455 Medium · 6.1 CWE-79 Mar 3, 2026

Cross-site Scripting (XSS) in Nodemailer Mailparser

Versions of the package mailparser before 3.9.3 are vulnerable to Cross-site Scripting (XSS) via the textToHtml() function due to the improper sanitisation of URLs in the email content. An attacker can execute arbitrary scripts in victim browsers by adding extra quote " to the URL with embedded malicious JavaScript code.

CVE-2025-14874 High · 7.5 CWE-703 Dec 18, 2025

Nodemailer: nodemailer: denial of service via crafted email address header

A flaw was found in Nodemailer. This vulnerability allows a denial of service (DoS) via a crafted email address header that triggers infinite recursion in the address parser.

CVE-2025-13033 High · 7.5 CWE-1286 Nov 14, 2025

Nodemailer: nodemailer: email to an unintended domain can occur due to interpretation conflict

A vulnerability was identified in the email parsing library due to improper handling of specially formatted recipient email addresses. An attacker can exploit this flaw by crafting a recipient address that embeds an external address within quotes. This causes the application to misdirect the email to the attacker's external address instead of the intended internal recipient. This could lead to a significant data leak of sensitive information and allow an attacker to bypass security filters and access controls.