A remote code execution vulnerability exists within osCommerce Online Merchant version 2.3.4.1 due to insecure default configuration and missing authentication in the installer workflow. By default, the /install/ directory remains accessible after installation. An unauthenticated attacker can invoke install_4.php, submit crafted POST data, and inject arbitrary PHP code into the configure.php file. When the application later includes this file, the injected payload is executed, resulting in full server-side compromise.

A remote code execution vulnerability exists within osCommerce Online Merchant version 2.3.4.1 due to insecure default configuration and missing authentication in the installer workflow. By default, the /install/ directory remains accessible after installation. An unauthenticated attacker can invoke install_4.php, submit crafted POST data, and inject arbitrary PHP code into the configure.php file. When the application later includes this file, the injected payload is executed, resulting in full server-side compromise.