What are the implications of allowing all users to write to a directory for file uploads in PHP?

Allowing all users to write to a directory for file uploads in PHP can pose a security risk as it may allow malicious users to upload harmful files to the server. To mitigate this risk, it is important to set appropriate file permissions on the upload directory to restrict write access to only the necessary users, such as the web server user.

// Set the correct permissions for the upload directory
chmod('/path/to/upload/directory', 0755);