Maho is a free and open source ecommerce platform. In Maho prior to 25.9.0, an authenticated staff user with access to the Dashboard and CatalogManage Products permissions can create a custom option on a listing with a file input field. By allowing file uploads with a .php extension, the user can use the filed to upload malicious PHP files, gaining remote code execution. Version 25.9.0 fixes the issue.
The product allows a file to be uploaded, but it relies on the file name or extension of the file to determine the appropriate behaviors. This could be used by attackers to cause the file to be misclassified and processed in a dangerous fashion.