Remote code injection in PHPMailer - CVE-2016-10033
Published: December 30, 2016 / Updated: July 7, 2025
Vulnerability identifier: #VU3118
CSH Severity: High
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Amber
CVE-ID: CVE-2016-10033
CWE-ID: CWE-94
Exploitation vector: Remote access
Exploit availability:
The vulnerability is being exploited in the wild
Vendor: phpmailer.sourceforge.net
Affected software:
PHPMailer
PHPMailer
Detailed vulnerability description
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to insufficient sanitization of user-supplied input passed via specially crafted “From” address to mailSend() function. A remote attacker can use backslashed double quote character (e.g. \") to pass additional commands to original mail command and execute them with privileges of the current web server user.
Successful exploitation of the vulnerability may result in system compromise.
How to mitigate CVE-2016-10033
Install the latest version 5.2.21 from vendor's website.
Sources
- http://packetstormsecurity.com/files/140291/PHPMailer-Remote-Code-Execution.html
- http://seclists.org/fulldisclosure/2016/Dec/78
- http://www.securityfocus.com/archive/1/archive/1/539963/100/0/threaded
- http://www.securityfocus.com/bid/95108
- https://developer.joomla.org/security-centre/668-20161205-phpmailer-security-advisory.html
- https://github.com/PHPMailer/PHPMailer/releases/tag/v5.2.18
- https://github.com/PHPMailer/PHPMailer/wiki/About-the-CVE-2016-10033-and-CVE-2016-10045-vulnerabilit...
- https://legalhackers.com/advisories/PHPMailer-Exploit-Remote-Code-Exec-CVE-2016-10033-Vuln.html
- https://www.drupal.org/psa-2016-004
- https://www.exploit-db.com/exploits/40968/
- https://www.exploit-db.com/exploits/40970/