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CVE-2016-10033

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.

Security Impact Summary

This vulnerability carries a CRITICAL severity rating with a CVSS v3.1 score of 9.8, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts confidentiality (data exposure), integrity (unauthorized modifications), and availability (service disruption) for affected systems. Impacting 3 products from phpmailer_project, from wordpress, from joomla organizations running these solutions should prioritize assessment and patching.

Historical Context

First disclosed in 2016, this vulnerability was reported during a period defined by widespread IoT adoption challenges, mobile security concerns, and the emergence of advanced persistent threat (APT) techniques. Contemporary mitigation strategies focused on secure development practices and third-party component vetting.

Published

2016-12-30T19:59:00.137

Last Modified

2026-04-21T16:27:03.000

Status

Analyzed

Source

[email protected]

Severity

CVSSv3.1: 9.8 (CRITICAL)

CVSSv2 Vector

AV:N/AC:L/Au:N/C:P/I:P/A:P

Access Vector: NETWORK
Access Complexity: LOW
Authentication: NONE
Confidentiality Impact: PARTIAL
Integrity Impact: PARTIAL
Availability Impact: PARTIAL

Exploitability Score

10.0

Impact Score

6.4

Weaknesses

Type: Primary
CWE-88
Type: Secondary
CWE-88

Affected Vendors & Products

Type	Vendor	Product	Version/Range	Vulnerable?
Application	phpmailer_project	phpmailer	< 5.2.18	Yes
Application	wordpress	wordpress	≤ 4.7	Yes
Application	joomla	joomla\!	≤ 3.6.5	Yes

References

http://packetstormsecurity.com/files/140291/PHPMailer-Remote-Code-Execution.html Exploit, Third Party Advisory, VDB Entry ([email protected])
http://packetstormsecurity.com/files/140350/PHPMailer-Sendmail-Argument-Injection.html Exploit, Third Party Advisory, VDB Entry ([email protected])
http://seclists.org/fulldisclosure/2016/Dec/78 Mailing List, Patch, Third Party Advisory ([email protected])
http://www.rapid7.com/db/modules/exploit/multi/http/phpmailer_arg_injection Exploit, Third Party Advisory ([email protected])
http://www.securityfocus.com/archive/1/539963/100/0/threaded Broken Link, Third Party Advisory, VDB Entry ([email protected])
http://www.securityfocus.com/bid/95108 Broken Link, Exploit, Third Party Advisory, VDB Entry ([email protected])
http://www.securitytracker.com/id/1037533 Broken Link, Third Party Advisory, VDB Entry ([email protected])
https://developer.joomla.org/security-centre/668-20161205-phpmailer-security-advisory.html Third Party Advisory ([email protected])
https://github.com/PHPMailer/PHPMailer/releases/tag/v5.2.18 Patch, Vendor Advisory ([email protected])
https://github.com/PHPMailer/PHPMailer/wiki/About-the-CVE-2016-10033-and-CVE-2016-10045-vulnerabilities Patch, Vendor Advisory ([email protected])
https://legalhackers.com/advisories/PHPMailer-Exploit-Remote-Code-Exec-CVE-2016-10033-Vuln.html Exploit, Patch, Third Party Advisory ([email protected])
https://www.drupal.org/psa-2016-004 Third Party Advisory ([email protected])
https://www.exploit-db.com/exploits/40968/ Exploit, Patch, Third Party Advisory, VDB Entry ([email protected])
https://www.exploit-db.com/exploits/40969/ Exploit, Third Party Advisory, VDB Entry ([email protected])
https://www.exploit-db.com/exploits/40970/ Exploit, Patch, Third Party Advisory, VDB Entry ([email protected])
https://www.exploit-db.com/exploits/40974/ Exploit, Third Party Advisory, VDB Entry ([email protected])
https://www.exploit-db.com/exploits/40986/ Exploit, Third Party Advisory, VDB Entry ([email protected])
https://www.exploit-db.com/exploits/41962/ Exploit, Third Party Advisory, VDB Entry ([email protected])
https://www.exploit-db.com/exploits/41996/ Exploit, Third Party Advisory, VDB Entry ([email protected])
https://www.exploit-db.com/exploits/42024/ Exploit, Third Party Advisory, VDB Entry ([email protected])
https://www.exploit-db.com/exploits/42221/ Exploit, Third Party Advisory, VDB Entry ([email protected])
http://packetstormsecurity.com/files/140291/PHPMailer-Remote-Code-Execution.html Exploit, Third Party Advisory, VDB Entry (af854a3a-2127-422b-91ae-364da2661108)
http://packetstormsecurity.com/files/140350/PHPMailer-Sendmail-Argument-Injection.html Exploit, Third Party Advisory, VDB Entry (af854a3a-2127-422b-91ae-364da2661108)
http://seclists.org/fulldisclosure/2016/Dec/78 Mailing List, Patch, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
http://www.rapid7.com/db/modules/exploit/multi/http/phpmailer_arg_injection Exploit, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
http://www.securityfocus.com/archive/1/539963/100/0/threaded Broken Link, Third Party Advisory, VDB Entry (af854a3a-2127-422b-91ae-364da2661108)
http://www.securityfocus.com/bid/95108 Broken Link, Exploit, Third Party Advisory, VDB Entry (af854a3a-2127-422b-91ae-364da2661108)
http://www.securitytracker.com/id/1037533 Broken Link, Third Party Advisory, VDB Entry (af854a3a-2127-422b-91ae-364da2661108)
https://developer.joomla.org/security-centre/668-20161205-phpmailer-security-advisory.html Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://github.com/PHPMailer/PHPMailer/releases/tag/v5.2.18 Patch, Vendor Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://github.com/PHPMailer/PHPMailer/wiki/About-the-CVE-2016-10033-and-CVE-2016-10045-vulnerabilities Patch, Vendor Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://legalhackers.com/advisories/PHPMailer-Exploit-Remote-Code-Exec-CVE-2016-10033-Vuln.html Exploit, Patch, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://www.drupal.org/psa-2016-004 Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://www.exploit-db.com/exploits/40968/ Exploit, Patch, Third Party Advisory, VDB Entry (af854a3a-2127-422b-91ae-364da2661108)
https://www.exploit-db.com/exploits/40969/ Exploit, Third Party Advisory, VDB Entry (af854a3a-2127-422b-91ae-364da2661108)
https://www.exploit-db.com/exploits/40970/ Exploit, Patch, Third Party Advisory, VDB Entry (af854a3a-2127-422b-91ae-364da2661108)
https://www.exploit-db.com/exploits/40974/ Exploit, Third Party Advisory, VDB Entry (af854a3a-2127-422b-91ae-364da2661108)
https://www.exploit-db.com/exploits/40986/ Exploit, Third Party Advisory, VDB Entry (af854a3a-2127-422b-91ae-364da2661108)
https://www.exploit-db.com/exploits/41962/ Exploit, Third Party Advisory, VDB Entry (af854a3a-2127-422b-91ae-364da2661108)
https://www.exploit-db.com/exploits/41996/ Exploit, Third Party Advisory, VDB Entry (af854a3a-2127-422b-91ae-364da2661108)
https://www.exploit-db.com/exploits/42024/ Exploit, Third Party Advisory, VDB Entry (af854a3a-2127-422b-91ae-364da2661108)
https://www.exploit-db.com/exploits/42221/ Exploit, Third Party Advisory, VDB Entry (af854a3a-2127-422b-91ae-364da2661108)
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2016-10033 US Government Resource (134c704f-9b21-4f2e-91b3-4a467353bcc0)

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For phpmailer_project's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.