Is CVE-2016-10033 in the CISA KEV catalog?

Yes. CVE-2016-10033 is on the CISA Known Exploited Vulnerabilities list, added 2025-07-07.

What is the CVSS severity of CVE-2016-10033?

CVE-2016-10033 has a CVSS v3 base score of 9.8 (CRITICAL).

What is the EPSS score for CVE-2016-10033?

CVE-2016-10033 has an EPSS score of 99.71% (100th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2016-10033?

Upgrade libphp-phpmailer on debian 11 to 5.2.14+dfsg-2.1 or later. Fixes are available for 2 affected products.

CVE & CISA-KEV Catalog

CVE-2016-10033

CRITICALCISA KEVEPSS 100th pctl

9.8

CVSS v3

NVD

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.

CWE-88

How to fix

Remediation Available

libphp-phpmailerDebian

Fixed in:5.2.14+dfsg-2.1CVE-2016-10033

libphp-phpmailerUbuntu

Fixed in:5.2.14+dfsg-1ubuntu0.1~esm1USN-5956-1

Fixed in:5.2.14+dfsg-2.3+deb9u2ubuntu0.1~esm1USN-5956-1

Fixed in:6.0.6-0.1ubuntu0.1~esm1USN-5956-1

Fixed in:6.2.0-2ubuntu0.1~esm1USN-5956-1

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

99.71%probability of exploitation in 30 days

100thpercentile

Very high risk: more likely to be exploited than 100% of all known CVEs.

Known Exploited Vulnerability (CISA KEV)

PHPMailer Command Injection Vulnerability

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.

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Remediation due: 2025-07-28

References

Patch6

Exploit11

Third-Party Advisory4

Government Resource1

cisa.gov

Related Vulnerabilities

Other CWE-88 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2022-36804	High	8.8	99%	KEV	Fix
CVE-2026-24061	Critical	9.8	99%	KEV	Fix
CVE-2007-0882	High	10.0	98%	-	-
CVE-2018-17456	Critical	9.8	97%	-	Fix
CVE-2018-19518	High	7.5	95%	-	Fix
CVE-2021-33564	Critical	9.8	72%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-21.