CVE-2016-10033

critical

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

https://www.drupal.org/psa-2016-004

https://developer.joomla.org/security-centre/668-20161205-phpmailer-security-advisory.html

http://seclists.org/fulldisclosure/2016/Dec/78

https://securityaffairs.com/179722/hacking/u-s-cisa-adds-mrlg-phpmailer-rails-ruby-on-rails-and-synacor-zimbra-collaboration-suite-flaws-to-its-known-exploited-vulnerabilities-catalog.html

https://www.cisa.gov/news-events/alerts/2025/07/07/cisa-adds-four-known-exploited-vulnerabilities-catalog

https://thehackernews.com/2025/07/cisa-adds-four-critical-vulnerabilities.html

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2016-10033

https://github.com/PHPMailer/PHPMailer/wiki/About-the-CVE-2016-10033-and-CVE-2016-10045-vulnerabilities

https://github.com/PHPMailer/PHPMailer/releases/tag/v5.2.18

Details

Source: Mitre, NVD

Published: 2016-12-30

Updated: 2025-10-22

Known Exploited Vulnerability (KEV)

Risk Information

CVSS v2

Base Score: 7.5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P

Severity: High

CVSS v3

Base Score: 9.8

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Severity: Critical

EPSS

EPSS: 0.9446