High

Zend-Mail remote code execution in zend-mail via Sendmail adapter

  • Disclosed: 07.06.2024
  • Updated: 11.10.2026 10:22

When using the zend-mail component to send email via the Zend\Mail\Transport\Sendmail transport, a malicious user may be able to inject arbitrary parameters to the system sendmail program. The attack is performed by providing additional quote characters within an address; when unsanitized, they can be interpreted as additional command line arguments, leading to the vulnerability.

The following example demonstrates injecting additional parameters to the sendmail binary via the From address:

php
use Zend\Mail;

$mail = new Mail\Message();
$mail->setBody('This is the text of the email.');

// inject additional parameters to sendmail command line
$mail->setFrom('"AAA\" params injection"@domain', 'Sender\'s name');

$mail->addTo('hacker@localhost', 'Name of recipient');
$mail->setSubject('TestSubject');

$transport = new Mail\Transport\Sendmail();
$transport->send($mail);

The attack works because zend-mail filters the email addresses using the RFC 3696 specification, where the string "AAA" params injection"@domain is considered a valid address. This validation is provided using the zend-validator component with the following parameters:

Zend\Validator\EmailAddress(
    Zend\Validator\Hostname::ALLOW_DNS | Zend\Validator\Hostname::ALLOW_LOCAL
)

The above accepts local domain with any string specified by double quotes as the local part. While this is valid per RFC 3696, due to the fact that sender email addresses are provided to the sendmail binary via the command line, they create the vulnerability described above.

Affected software

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PlatformPackageVulnerable versionsFixed in
Composer package zendframework/zend-mail >= 2.0.0, < 2.4.11, >= 2.5.0, < 2.7.2 2.4.11, 2.7.2

References

CVSS score 8.8/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE)
CWE-74
Platform
Composer
Package
zendframework/zend-mail
Disclosed
07.06.2024
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-cxf7-m5g2-v594 - CC BY 4.0

Vulnerability history: zendframework/zend-mail

All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.

Total entries
2
First → latest
05.2022 06.2024
Without a fix
0
Exploited in attacks
0

Severity breakdown

  • Critical 1
  • High 1

Disclosures per year

  1. 2022: 1
  2. 2023: 0
  3. 2024: 1
  4. 2025: 0
  5. 2026: 0
  1. Zend-Mail remote code execution in zend-mail via Sendmail adapter this entry
    High · 8.8 ghsa-cxf7-m5g2-v594 >= 2.0.0, < 2.4.11, >= 2.5.0, < 2.7.2 2.4.11, 2.7.2
  2. Critical · 9.8 CVE-2016-10034 < 2.4.11, >= 2.5, <= 2.5.2, >= 2.6, <= 2.6.2, >= 2.7, < 2.7.2 2.4.11, 2.7.2

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