What are common pitfalls when implementing multiple file uploads in PHP?

Common pitfalls when implementing multiple file uploads in PHP include not properly handling file size limits, not sanitizing file names to prevent security vulnerabilities, and not checking for file type validation. To solve these issues, you should set appropriate file size limits, sanitize file names using functions like `filter_var()` or `preg_replace()`, and validate file types using functions like `pathinfo()` or MIME type checking. 

// Set file size limit
$maxFileSize = 5 * 1024 * 1024; // 5MB

// Sanitize file name
$fileName = preg_replace("/[^a-zA-Z0-9._-]/", "", $_FILES['file']['name']);

// Validate file type
$allowedTypes = ['image/jpeg', 'image/png', 'image/gif'];
$fileType = mime_content_type($_FILES['file']['tmp_name']);
if (!in_array($fileType, $allowedTypes)) {
    die("Invalid file type. Allowed types: jpeg, png, gif");
}

Keywords

file uploads PHP multiple pitfalls implementation

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