CVE-2016-10033

CRITICAL
9.8
CVSS Score
Published: December 30, 2016 at 07:00 PM UTC
Updated: June 17, 2026 at 12:38 AM UTC
3 products affected across 3 vendorsJoomla!WordPressPhpmailer

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Severity
CRITICAL9.8
Exploitation
CISA KEV
Exploit prediction
EPSS 100%
SSVC
Active

Actively Exploited

CISA Known Exploited Vulnerabilities (KEV) Catalog

EPSS Score99.7%

EPSS (Exploit Prediction Scoring System) estimates a 99.7% chance this CVE is exploited in the wild within the next 30 days — higher than 100% of all CVEs. It complements CVSS: a high EPSS on a mid-severity CVE can still be urgent.

PHPMailer contains a command injection vulnerability because it fails to sanitize user-supplied input. Specifically, this issue affects the 'mail()' function of 'class.phpmailer.php' script. An attacker can exploit this issue to execute arbitrary code within the context of the application. Failed exploit attempts will result in a denial-of-service condition.

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.
Ransomware Use
Unknown
Added to KEV
Jul 7, 2025
Remediation Due
Jul 28, 2025
456 days overdue

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

1.5.0 ≤ v ≤ 3.6.5
v < 5.2.18
Affected range stops below 5.2.18, so it looks safe — our inference, not a vendor statement
v ≤ 4.7

References (22)

Mailing Listx_refsource_FULLDISCPatchThird Party Advisory
http://seclists.org/fulldisclosure/2016/Dec/78
Mailing Listx_refsource_BUGTRAQBroken LinkThird Party AdvisoryVDB Entry
http://www.securityfocus.com/archive/1/539963/100/0/threaded
VDB Entryx_refsource_BIDBroken LinkExploitThird Party Advisory
http://www.securityfocus.com/bid/95108
VDB Entryx_refsource_SECTRACKBroken LinkThird Party Advisory
http://www.securitytracker.com/id/1037533

SSVC — Action Prioritization

SSVCActiveAutomatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

9.8CRITICALCISA-ADP
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-88

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