CVE-2021-43258: Malicious File Upload

CartView.php in ChurchInfo 1.3.0 allows attackers to achieve remote code execution through insecure uploads. This requires authenticated access tot he ChurchInfo application. Once authenticated, a user can add names to their cart, and compose an email. Uploading an attachment for the email stores the attachment on the site in the /tmpattach/ folder where it can be accessed with a GET request. There are no limitations on files that can be attached, allowing for malicious PHP code to be uploaded and interpreted by the server.