#VU54171 Code Injection in PHPMailer - CVE-2021-3603
Published: June 16, 2021
Vulnerability identifier: #VU54171
Vulnerability risk: High
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber
CVE-ID: CVE-2021-3603
CWE-ID: CWE-94
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
PHPMailer
PHPMailer
Software vendor:
phpmailer.sourceforge.net
phpmailer.sourceforge.net
Description
The vulnerability allows a remote attacker to execute arbitrary PHP code on the target system.
The vulnerability exists due to improper input validation. If the $patternselect parameter to validateAddress() is set to 'php' (the default, defined by PHPMailer::$validator), and the global namespace contains a function called php, it will be called in preference to the built-in validator of the same name. A remote attacker can send a specially crafted request and execute arbitrary code on the target system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
Remediation
Install updates from vendor's website.