Advanced Custom Fields <= 5.12.2 - File Upload

The Advanced Custom Fields plugin for WordPress has a file upload vulnerability in versions up to, and including, 5.12.2. This allows users without the upload_files capability, such as contributors, or unauthenticated users in cases where a frontend form is added to the site, to upload allowed file types. The upload is handled by WordPress so file type and extension checks still occur, though this could potentially be used by high-privileged users in certain locked-down configurations to bypass other security mechanisms and upload dangerous file types.