CVE-2016-10033

PHPMailer Command Injection Vulnerability

IN CISA KEV

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.

Vendor: PHP
Product: PHPMailer
CVSS 3.1: 9.8 (critical), scored by NVD (primary)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 3.1: 9.8 (critical), scored by 134c704f-9b21-4f2e-91b3-4a467353bcc0CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE: CWE-88
Published: 2016-12-30
NVD modified: 2026-06-17
NVD status: Analyzed

CISA KEV

Date added: 2025-07-07
Due date: 2025-07-28
Ransomware use: Unknown
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.

EPSS

100% chance of exploitation in the next 30 days (percentile 99th)

FIRST EPSS, updated 17 Oct 2026. About EPSS

CVSS is severity, EPSS is likelihood, KEV means already exploited. EPSS is a statistical probability, not a certainty: a low score does not make a bug safe, and a high one does not prove it is being exploited.

References

seclists.org (Mailing List, Patch, Third Party Advisory)
www.securityfocus.com (Broken Link, Third Party Advisory, VDB Entry)
www.securitytracker.com (Broken Link, Third Party Advisory, VDB Entry)
developer.joomla.org (Third Party Advisory)
github.com (Patch, Vendor Advisory)
github.com (Patch, Vendor Advisory)
www.drupal.org (Third Party Advisory)
seclists.org (Mailing List, Patch, Third Party Advisory)
www.securityfocus.com (Broken Link, Third Party Advisory, VDB Entry)
www.securitytracker.com (Broken Link, Third Party Advisory, VDB Entry)
developer.joomla.org (Third Party Advisory)
github.com (Patch, Vendor Advisory)

Data last updated 18 Oct 2026. Sources: NVD API 2.0, CISA KEV catalog, FIRST EPSS. Links: NVD, CISA KEV. Metadata only. ThreatWire does not host exploit code.