CVE-2016-10033

phpmailer project phpmailer, wordpress, joomla!

Published 30 Dec 2016 · updated 17 Jun 2026 · Analyzed

9.8 Critical · CVSS 3.1, NVD

Exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on 7 Jul 2025, with a remediation deadline of 28 Jul 2025 for US federal agencies.

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.

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.

References

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