PHPMailer Command Injection Vulnerability
n/a — n/a
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.
9.8
99.7%
Vector breakdown
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Published
- Dec 30, 2016
- Modified
- Jun 17, 2026
- Added to KEV
- Jul 7, 2025
- Federal patch due
- Jul 28, 2025
CISA 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.
Weakness classification
Affected packages
Proof-of-concept & exploitation references
8 foundWeaponization
Public repositories whose name or description references CVE-2016-10033, found via a live GitHub search at request time. These are community-sourced signals, not a verified working exploit - cross-check each one before relying on it, and treat higher star counts and recent activity as (weak) corroboration, not proof.
- opsxcq/exploit-CVE-2016-10033★ 408
PHPMailer < 5.2.18 Remote Code Execution exploit and vulnerable container
updated Oct 12, 2026
- GeneralTesler/CVE-2016-10033★ 9
RCE against WordPress 4.6; Python port of https://exploitbox.io/vuln/WordPress-Exploit-4-6-RCE-CODE-EXEC-CVE-2016-10033.html
updated Aug 12, 2024
- Zenexer/safeshell★ 8
Prevent PHP vulnerabilities similar to CVE-2016-10033 and CVE-2016-10045.
updated Mar 26, 2020
- dmonst3r/CVE_2016-10033★ 7
Exploiting PHPMail with back connection (reverse shell) from the target
updated Jan 10, 2023
- 0x00-0x00/CVE-2016-10033★ 6
PHPMailer < 5.2.18 Remote Code Execution Exploit
updated Jan 12, 2026
- pedro823/cve-2016-10033-45★ 2
Exploits CVE-2016-10033 and CVE-2016-10045
updated May 17, 2025
- chipironcin/CVE-2016-10033★ 1
Code and vulnerable WordPress container for exploiting CVE-2016-10033
updated Jan 12, 2026
- j4k0m/CVE-2016-10033★ 1
Remote Code Execution vulnerability in PHPMailer.
updated Sep 7, 2021
References
Frequently asked questions
What is CVE-2016-10033?
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.
How severe is CVE-2016-10033?
CVE-2016-10033 has a CVSS base score of 9.8 out of 10 (CVSS 3.1).
Is CVE-2016-10033 actively exploited in the wild?
Yes. CVE-2016-10033 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added Jul 7, 2025, meaning CISA has confirmed evidence of active exploitation.
What is the EPSS score for CVE-2016-10033?
99.7% - meaning FIRST.org's EPSS model estimates a 99.7% probability this vulnerability will be exploited in the wild within 30 days (100% percentile among all scored CVEs).
Is there exploit tooling available for CVE-2016-10033?
Yes - a public Nuclei template referencing CVE-2016-10033 exist in public repositories we checked. We also found 8 public GitHub repositories referencing this CVE.
What type of vulnerability is CVE-2016-10033?
CVE-2016-10033 is classified under CWE-88 (CWE-88 Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')).
Cross-checked against
Impactr finds and proves whether CVE-2016-10033 - or flaws like it - are actually reachable in your own web apps and APIs, with a reproducible exploit as evidence.
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