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CVE-2016-10033

CRITICAL severity · CVSS 9.8 · CWE-88 · actively exploited (CISA KEV)
9.8CVSS CRITICAL ● exploited
🔴 Actively exploited in the wild (CISA Known Exploited Vulnerabilities). Added to KEV 2025-07-07. US federal agencies must patch by 2025-07-28.

Summary

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.

Impact & exploitability

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
Confidentiality impactHigh
Integrity impactHigh
Availability impactHigh
Exploit probability (EPSS)94%

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

Affected products we track (1)

Recommendation

This vulnerability is being actively exploited in the wild — patch affected products urgently. Open any affected product above for its exact safe version.

Official patch: http://seclists.org/fulldisclosure/2016/Dec/78 ↗

Last checked: Wed, 10 Jun 2026 22:18:30 UTC