# CVE-2016-10033: PHPMailer Command Injection Vulnerability

> CVE-2016-10033: PHPMailer Command Injection Vulnerability. CVSS 9.8 (CVSS 3.1), in CISA KEV.

Canonical: https://rewindex.com/cve/CVE-2016-10033
Last updated: 2025-10-21T23:55:47Z

- Published: 2016-12-30 19:00 UTC · Updated: 2025-10-21 23:55 UTC · Assigner: mitre
- CVSS: 9.8 (CVSS 3.1) · Severity: Critical · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS: 99.7%, 100th percentile (scored 2026-10-25)
- CISA KEV: yes, added 2025-07-07, federal due date 2025-07-28, ransomware use: Unknown

## 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.

## CISA required action

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

## Affected vendors and products

- PHP: PHPMailer

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2016-10033)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2016-10033)
- [http://packetstormsecurity.com/files/140291/PHPMailer-Remote-Code-Execution.html](http://packetstormsecurity.com/files/140291/PHPMailer-Remote-Code-Execution.html)
- [http://packetstormsecurity.com/files/140350/PHPMailer-Sendmail-Argument-Injection.html](http://packetstormsecurity.com/files/140350/PHPMailer-Sendmail-Argument-Injection.html)
- [https://developer.joomla.org/security-centre/668-20161205-phpmailer-security-advisory.html](https://developer.joomla.org/security-centre/668-20161205-phpmailer-security-advisory.html)
- [http://seclists.org/fulldisclosure/2016/Dec/78](http://seclists.org/fulldisclosure/2016/Dec/78)
- [https://github.com/PHPMailer/PHPMailer/releases/tag/v5.2.18](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://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://legalhackers.com/advisories/PHPMailer-Exploit-Remote-Code-Exec-CVE-2016-10033-Vuln.html)
- [https://www.drupal.org/psa-2016-004](https://www.drupal.org/psa-2016-004)
- [https://www.exploit-db.com/exploits/40968/](https://www.exploit-db.com/exploits/40968/)
- [https://www.exploit-db.com/exploits/40969/](https://www.exploit-db.com/exploits/40969/)
- [https://www.exploit-db.com/exploits/40970/](https://www.exploit-db.com/exploits/40970/)
- [https://www.exploit-db.com/exploits/40974/](https://www.exploit-db.com/exploits/40974/)
- [https://www.exploit-db.com/exploits/40986/](https://www.exploit-db.com/exploits/40986/)
- [https://www.exploit-db.com/exploits/41962/](https://www.exploit-db.com/exploits/41962/)
- [https://www.exploit-db.com/exploits/41996/](https://www.exploit-db.com/exploits/41996/)
- [https://www.exploit-db.com/exploits/42024/](https://www.exploit-db.com/exploits/42024/)
- [https://www.exploit-db.com/exploits/42221/](https://www.exploit-db.com/exploits/42221/)
- [http://www.rapid7.com/db/modules/exploit/multi/http/phpmailer\_arg\_injection](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/archive/1/539963/100/0/threaded)
- [http://www.securityfocus.com/bid/95108](http://www.securityfocus.com/bid/95108)
- [http://www.securitytracker.com/id/1037533](http://www.securitytracker.com/id/1037533)

---

_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


---
Canonical: https://rewindex.com/cve/CVE-2016-10033 · Markdown: https://rewindex.com/cve/CVE-2016-10033.md · JSON: https://rewindex.com/api/v1/cves/CVE-2016-10033 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T02:01:55.634Z