The vulnerability stems from the create() function's improper validation of the productData parameter. The function passes this user-controlled parameter directly to property_exists(), which triggers class autoloading when the input is a non-object. The autoloader then attempts to include a file based on the attacker-provided string (via PHP's class name resolution), enabling arbitrary code execution. Multiple sources (CVE description, Minded Security blog, and KarmaInsecurity advisory) explicitly reference this function and the property_exists() call as the vulnerability root cause.