Zen Cart 1.3.8a, 1.3.8, and earlier does not require administrative authentication for admin/record_company.php, which allows remote attackers to execute arbitrary code by uploading a .php file via the record_company_image parameter in conjunction with a PATH_INFO of password_forgotten.php, then accessing this file via a direct request to the file in images/.
https://exchange.xforce.ibmcloud.com/vulnerabilities/51316
http://www.zen-cart.com/forum/showthread.php?t=130161
http://www.zen-cart.com/forum/attachment.php?attachmentid=5965