Phpmailer
CVE-2016-10033
CRITICAL
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Argument sanitization
|
| Impact | CVSS score of 9.8 (CRITICAL). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. CISA has confirmed active exploitation in the wild. Public proof-of-concept exploit code is available. EPSS exploitation probability: 94.47%. |
| Exploit ScenarioDerived | This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the critical-severity affected system. |
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Alert meAnalysisAI
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 \". Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Actively exploited in the wild (cisa kev) and public exploit code available.
RemediationAI
A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in composer
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
This vulnerability is classified under CWE-88. 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 products include: Phpmailer Project Phpmailer, Wordpress, Joomla Joomla\!. Version information: before 5.2.18.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
Lifecycle Timeline
2DescriptionCVE.org
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.
Threat Intelligence Overview
NVD
CVE.org
CISA KEV
EPSS
Exploit-DB
GitHub
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.
Affected Products (CPE)CVE.org
The isMail transport in PHPMailer before 5.2.20 might allow remote attackers to pass extra parameters to the mail comman
PHPMailer before 6.1.6 contains an output escaping bug when the name of a file attachment contains a double quote charac
PHPMailer 5.2.23 has XSS in the "From Email Address" and "To Email Address" fields of code_generator.php. Rated medium s
An issue was discovered in PHPMailer before 5.2.22. Rated medium severity (CVSS 5.5), this vulnerability is low attack c
PHPMailer before 5.2.27 and 6.x before 6.0.6 is vulnerable to an object injection attack. Rated high severity (CVSS 8.8)
PHPMailer 6.4.1 and earlier contain a vulnerability that can result in untrusted code being called (if such code is inje
PHPMailer before 6.5.0 on Windows allows remote code execution if lang_path is untrusted data and has a UNC pathname. Ra
Multiple CRLF injection vulnerabilities in PHPMailer before 5.2.14 allow attackers to inject arbitrary SMTP commands via