CVE-2016-10033
CRITICALCISA KEVEPSS 100th pctlDescription
The mailSend function in the isMail transport in PHPMailer before 5.2.18 might allow remote attackers to pass extra parameters to the mail command and consequently execute arbitrary code via a \" (backslash double quote) in a crafted Sender property.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploit Intelligence
Very high risk: more likely to be exploited than 100% of all known CVEs.
PHPMailer Command Injection Vulnerability
PHPMailer contains a command injection vulnerability because it fails to sanitize user-supplied input. Specifically, this issue affects the 'mail()' function of 'class.phpmailer.php' script. An attacker can exploit this issue to execute arbitrary code within the context of the application. Failed exploit attempts will result in a denial-of-service condition.
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Remediation due: 2025-07-28
References
- http://packetstormsecurity.com/files/140291/PHPMailer-Remote-Code-Execution.html
- http://packetstormsecurity.com/files/140350/PHPMailer-Sendmail-Argument-Injection.html
- http://seclists.org/fulldisclosure/2016/Dec/78
- http://www.rapid7.com/db/modules/exploit/multi/http/phpmailer_arg_injection
- http://www.securityfocus.com/archive/1/539963/100/0/threaded
- http://www.securityfocus.com/bid/95108
- http://www.securitytracker.com/id/1037533
- 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-vulnerabilities
- 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/40969/
- https://www.exploit-db.com/exploits/40970/
- https://www.exploit-db.com/exploits/40974/
- https://www.exploit-db.com/exploits/40986/
- https://www.exploit-db.com/exploits/41962/
- https://www.exploit-db.com/exploits/41996/
- https://www.exploit-db.com/exploits/42024/
- https://www.exploit-db.com/exploits/42221/
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2016-10033
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Start freeThis product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-21.