CubeCart is an ecommerce software solution. Prior to 6.7.0, an Authenticated Arbitrary File Upload vulnerability exists in the REST API File Manager endpoint (POST /api/v1/files) of CubeCart. The endpoint allows any holder of an API key with files:rw permission to upload PHP source files into the web-accessible images/source/ directory, where they are executed by the web server. Combined with a path-traversal flaw in the same endpoint's filepath parameter, a single API request writes a webshell anywhere the webserver process can write — including the document root — yielding full Remote Code Execution. This vulnerability is fixed in 6.7.0.