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
- 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
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
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. Refreshed daily.