CVE-2016-10033
9.8, critical Known exploitedPHPMailer Command Injection Vulnerability
- CVSS
- 9.8, critical critical CVSS v3.1
- EPSS, next 30 days
- 100% higher than 99.9% of scored CVEs
- Exploitation
- Confirmed in the wild
- Published
- 30 Dec 20169 years ago
Known exploited
CISA added this to the Known Exploited Vulnerabilities Catalog on 7 Jul 2025. US federal agencies had to remediate by 28 Jul 2025, a deadline that has passed.
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.
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.
Details
- Vendor
- PHP and 2 more
- Product
- Phpmailer
- Weakness
- CWE-88 (opens in a new tab)
- Status
- Analyzed
- Updated
- 17 Jun 2026
- Assigner
- cve@mitre.org
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References 22
Exploit code 15
- packetstormsecurity.com /files/140291/PHPMailer-Remote-Code-Execution.html (opens in a new tab)
- packetstormsecurity.com /files/140350/PHPMailer-Sendmail-Argument-Injection.html (opens in a new tab)
- seclists.org /fulldisclosure/2016/Dec/78 (opens in a new tab)
- rapid7.com /db/modules/exploit/multi/http/phpmailer_arg_injection (opens in a new tab)
- securityfocus.com /bid/95108 (opens in a new tab)
- legalhackers.com /advisories/PHPMailer-Exploit-Remote-Code-Exec-CVE-2016-10033-Vuln.html (opens in a new tab)
- exploit-db.com /exploits/40968/ (opens in a new tab)
- exploit-db.com /exploits/40969/ (opens in a new tab)
7 more
- exploit-db.com /exploits/40970/ (opens in a new tab)
- exploit-db.com /exploits/40974/ (opens in a new tab)
- exploit-db.com /exploits/40986/ (opens in a new tab)
- exploit-db.com /exploits/41962/ (opens in a new tab)
- exploit-db.com /exploits/41996/ (opens in a new tab)
- exploit-db.com /exploits/42024/ (opens in a new tab)
- exploit-db.com /exploits/42221/ (opens in a new tab)
Patches and fixes 2
Advisories 4
The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.
Other PHP CVEs
Every PHP CVE we holdSame vendor in what we hold, not a known link between the flaws.
- CVE-2019-11043 PHP FastCGI Process Manager (FPM) Buffer Overflow Vulnerability KEV EPSS 100% 9.8, critical
- CVE-2012-1823 PHP-CGI Query String Parameter Vulnerability KEV EPSS 100% 9.8, critical
Beyond this page
Is CVE-2016-10033 in your network?
This page tells you how dangerous CVE-2016-10033 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.
CVE-2016-10033 is in the CISA catalogue of exploited vulnerabilities: attackers are already exploiting it.
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EXYS7600 OCELOT
Find it before attackers do
Ocelot scans your network on a schedule and reports every vulnerability it finds by its CVE identifier, with its CVSS score and how many of your hosts are affected. A finding like CVE-2016-10033 comes with the devices to patch.
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EXYS7950 KONDRA
Detect it if it's exploited
Until the patch is applied, Kondra monitors your network, events and endpoints in real time. It keeps an inventory of the software installed on every endpoint, and its anomaly detection rules flag what an attacker does once inside.
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Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 16 Oct 2026, not the live upstream state.