How severe is CVE-2016-10045?

CVE-2016-10045 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2016-10045?

CVE-2016-10045 affects the following packages: phpmailer/phpmailer (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2016-10045?

Update phpmailer/phpmailer to version 5.2.20 or later. Run your dependency manager's update command and verify no transitive dependencies pin the vulnerable version. Use O3 Security's SCA scanner to confirm the fix is applied across your entire dependency tree.

Is CVE-2016-10045 actively exploited in the wild?

Yes. There are 10 known exploit references for CVE-2016-10045, including 3 documented proof-of-concept exploits on Exploit-DB and 7 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2016-10045?

CVE-2016-10045 has an EPSS (Exploit Prediction Scoring System) score of 93.1%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

What type of vulnerability is CVE-2016-10045?

CVE-2016-10045 is classified as CWE-77 (CWE-77). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2016-10045 published, and has it been updated?

CVE-2016-10045 was published on December 30, 2016 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

CVE-2016-10045

CRITICAL

Remote code execution in PHPMailer

Also known asGHSA-4pc3-96mx-wwc8

Published

Dec 30, 2016

Updated

Apr 10, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

10 known

EPSS Exploitation Probability

via FIRST.org ↗

93.1%probability of exploitation in next 30 days

Very High Risk100th percentile-0.34%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

🐘phpmailer/phpmailer

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

The isMail transport in PHPMailer before 5.2.20 might allow remote attackers to pass extra parameters to the mail command and consequently execute arbitrary code by leveraging improper interaction between the escapeshellarg function and internal escaping performed in the mail function in PHP. NOTE: this vulnerability exists because of an incorrect fix for CVE-2016-10033.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`phpmailer/phpmailer`	≥ 5.0.0&&< 5.2.20	5.2.20

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

EDB-40986webappsphp

PHPMailer < 5.2.20 / SwiftMailer < 5.4.5-DEV / Zend Framework / zend-mail < 2.4.11 - 'AIO' 'PwnScriptum' Remote Code Execution

by Dawid Golunski · Jan 2, 2017

Exploit-DB Source

EDB-42221webappsphp

PHPMailer < 5.2.20 with Exim MTA - Remote Code Execution

by phackt_ul · Jun 21, 2017

Exploit-DB Source

EDB-40969webappsphp

PHPMailer < 5.2.20 - Remote Code Execution

by Dawid Golunski · Dec 27, 2016

Exploit-DB Source

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2016-10045 in your stack?

O3 detects CVE-2016-10045 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my stack How O3 SCA works

CVSS Score

9.8/10

CVSS v3 base score

Vector breakdown

AV:Attack Vector

Network

AC:Attack Complexity

Low

PR:Privileges Required

None

UI:User Interaction