CVE-2016-10033
PHPMailer Command Injection Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 28 July 2025). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
Description
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 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 99.71% probability · 100th percentile
- Public exploits
- 9 in Exploit-DB · verified · first 25 December 2016
- CISA KEV
- Listed 7 July 2025 · due 28 July 2025
- Weakness
- CWE-88
- Affected
- phpmailer project/phpmailer · wordpress/wordpress · joomla/joomla\!
- Source
- cve@mitre.org
EPSS 99.7% since 30 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
CISA notes
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. This vulnerability could affect an open-source component, third-party library, protocol, or proprietary implementation that could be used by different products. For more information, please see: https://github.com/PHPMailer/PHPMailer/releases/tag/v5.2.18 ; https://github.com/advisories/GHSA-5f37-gxvh-23v6 ; https://nvd.nist.gov/vuln/detail/CVE-2016-10033
Public exploits (9)
Entries in Exploit-DB that cite this CVE. Links go to the Exploit-DB page and to the file in the public repository; nothing is hosted here. A verified tick means the Exploit-DB team confirmed the exploit works against the stated version.
| EDB-ID | Title | Type | Published | Verified |
|---|---|---|---|---|
| EDB-42221source ↗ | PHPMailer < 5.2.20 with Exim MTA - Remote Code Executionphp · phackt_ul | webapps | 21 June 2017 | no |
| EDB-42024source ↗ | WordPress Plugin PHPMailer 4.6 - Host Header Command Injection (Metasploit)php · Metasploit | remote | 17 May 2017 | yes |
| EDB-41996source ↗ | Vanilla Forums < 2.3 - Remote Code Executionphp · Dawid Golunski | remote | 11 May 2017 | no |
| EDB-41962source ↗ | WordPress Core 4.6 - Remote Code Executionlinux · Dawid Golunski | webapps | 3 May 2017 | no |
| EDB-40986source ↗ | PHPMailer < 5.2.20 / SwiftMailer < 5.4.5-DEV / Zend Framework / zend-mail < 2.4.11 - 'AIO' 'PwnScriptum' Remote Code Executionphp · Dawid Golunski | webapps | 2 January 2017 | no |
| EDB-40974source ↗ | PHPMailer < 5.2.18 - Remote Code Executionphp · anarc0der | webapps | 29 December 2016 | no |
| EDB-40969source ↗ | PHPMailer < 5.2.20 - Remote Code Executionphp · Dawid Golunski | webapps | 27 December 2016 | no |
| EDB-40968source ↗ | PHPMailer < 5.2.18 - Remote Code Executionphp · Dawid Golunski | webapps | 26 December 2016 | yes |
| EDB-40970source ↗ | PHPMailer < 5.2.18 - Remote Code Executionphp · Dawid Golunski | webapps | 25 December 2016 | no |
References
- http://packetstormsecurity.com/files/140291/PHPMailer-Remote-Code-Execution.htmlExploit, Third Party Advisory, VDB Entry
- http://packetstormsecurity.com/files/140350/PHPMailer-Sendmail-Argument-Injection.htmlExploit, Third Party Advisory, VDB Entry
- http://seclists.org/fulldisclosure/2016/Dec/78Mailing List, Patch, Third Party Advisory
- http://www.rapid7.com/db/modules/exploit/multi/http/phpmailer_arg_injectionExploit, Third Party Advisory
- http://www.securityfocus.com/archive/1/539963/100/0/threadedBroken Link, Third Party Advisory, VDB Entry
- http://www.securityfocus.com/bid/95108Broken Link, Exploit, Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1037533Broken Link, Third Party Advisory, VDB Entry
- https://developer.joomla.org/security-centre/668-20161205-phpmailer-security-advisory.htmlThird Party Advisory
- https://github.com/PHPMailer/PHPMailer/releases/tag/v5.2.18Patch, Vendor Advisory
- https://github.com/PHPMailer/PHPMailer/wiki/About-the-CVE-2016-10033-and-CVE-2016-10045-vulnerabilitiesPatch, Vendor Advisory
- https://legalhackers.com/advisories/PHPMailer-Exploit-Remote-Code-Exec-CVE-2016-10033-Vuln.htmlExploit, Patch, Third Party Advisory
- https://www.drupal.org/psa-2016-004Third Party Advisory
- https://www.exploit-db.com/exploits/40968/Exploit, Patch, Third Party Advisory, VDB Entry
- https://www.exploit-db.com/exploits/40969/Exploit, Third Party Advisory, VDB Entry
- https://www.exploit-db.com/exploits/40970/Exploit, Patch, Third Party Advisory, VDB Entry
- https://www.exploit-db.com/exploits/40974/Exploit, Third Party Advisory, VDB Entry
- https://www.exploit-db.com/exploits/40986/Exploit, Third Party Advisory, VDB Entry
- https://www.exploit-db.com/exploits/41962/Exploit, Third Party Advisory, VDB Entry
- https://www.exploit-db.com/exploits/41996/Exploit, Third Party Advisory, VDB Entry
- https://www.exploit-db.com/exploits/42024/Exploit, Third Party Advisory, VDB Entry
- https://www.exploit-db.com/exploits/42221/Exploit, Third Party Advisory, VDB Entry
- http://packetstormsecurity.com/files/140291/PHPMailer-Remote-Code-Execution.htmlExploit, Third Party Advisory, VDB Entry
- http://packetstormsecurity.com/files/140350/PHPMailer-Sendmail-Argument-Injection.htmlExploit, Third Party Advisory, VDB Entry
- http://seclists.org/fulldisclosure/2016/Dec/78Mailing List, Patch, Third Party Advisory
- http://www.rapid7.com/db/modules/exploit/multi/http/phpmailer_arg_injectionExploit, Third Party Advisory
- http://www.securityfocus.com/archive/1/539963/100/0/threadedBroken Link, Third Party Advisory, VDB Entry
- http://www.securityfocus.com/bid/95108Broken Link, Exploit, Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1037533Broken Link, Third Party Advisory, VDB Entry
- https://developer.joomla.org/security-centre/668-20161205-phpmailer-security-advisory.htmlThird Party Advisory
- https://github.com/PHPMailer/PHPMailer/releases/tag/v5.2.18Patch, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.