PHP · PHPMailer
CVE-2016-10033
PHPMailer Command Injection Vulnerability
CISA KEV record
- CISA date added
- 2025-07-07
- CISA due date
- 2025-07-28
- Known ransomware use
- Unknown
NVD risk context
9.8 CRITICAL
CVSS is a technical severity score. CISA’s KEV status remains the evidence that this vulnerability is known to be exploited.
Description
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.
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.
NVD reference index
Vendor and remediation references
NVD has tagged these sources as vendor advisories, patches, mitigations, or release notes.
- http://seclists.org/fulldisclosure/2016/Dec/78 ↗
- 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.exploit-db.com/exploits/40968/ ↗
- https://www.exploit-db.com/exploits/40970/ ↗
Other NVD references (16)
- http://packetstormsecurity.com/files/140291/PHPMailer-Remote-Code-Execution.html ↗
- http://packetstormsecurity.com/files/140350/PHPMailer-Sendmail-Argument-Injection.html ↗
- 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://www.drupal.org/psa-2016-004 ↗
- https://www.exploit-db.com/exploits/40969/ ↗
- 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 ↗
MITRE CWE context
CWE classification
The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.
View official MITRE CWE details ↗The product constructs a string for a command to be executed by a separate component in another control sphere, but it does not properly delimit the intended arguments, options, or switches within that command string.
View official MITRE CWE details ↗NVD record timing
NVD record timeline
These dates describe NVD’s record, not CISA’s KEV addition or remediation due date.
- NVD published
- Dec 30, 2016, 07:59 PM UTC When NVD first published this CVE record.
- NVD last updated
- Jun 17, 2026, 12:38 AM UTC When NVD last changed its analysis or record data.
Advanced: view the technical CVSS vector
This standardized code is intended for security tools and technical analysts. The plain-language risk summary above explains its main points.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA notes
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