Drag/Drop Multiple File Upload
Insufficient file type validation occurs when custom blacklist types are configured, as the system replaces the default dangerous extension denylist instead of merging with it. Additionally, the `wpcf7 antiscript file name()` function can be bypassed using filenames containing non-ASCII characters. This allows unauthenticated attackers to upload arbitrary files, such as PHP files, to the server, potentially leading to remote code execution.