Input validation error in PHPMailer - CVE-2021-34551
Published: June 16, 2021
Vulnerability identifier: #VU54170
CSH Severity: Medium
CVSS v4: 9.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2021-34551
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to compromise the affected system.
The vulnerability exists due to insufficient validation of user-supplied input within the setLanguage() method when processing the $lang_path parameter on a Windows system. A remote attacker can pass specially crafted input to the application, set a UNC path via the affected parameter and execute arbitrary PHP code on the system.
Affected software
PHPMailer
Moodle
Kirby
Fedora
php-phpmailer6
Moodle
Kirby
Fedora
php-phpmailer6
How to mitigate CVE-2021-34551
Install updates from vendor's website.
PHPMailer - update to 6.5.0
Kirby - update to 3.5.7
Moodle - addressed in versions 3.9.13, 3.10.10, 3.11.6
php-phpmailer6 - addressed in versions 6.5.0-1.fc33, 6.5.0-1.fc34
Kirby - update to 3.5.7
Moodle - addressed in versions 3.9.13, 3.10.10, 3.11.6
php-phpmailer6 - addressed in versions 6.5.0-1.fc33, 6.5.0-1.fc34