What are the potential pitfalls of not understanding why escaping characters are necessary in PHP?

When escaping characters are not properly understood in PHP, it can lead to security vulnerabilities such as SQL injection attacks or cross-site scripting (XSS) attacks. It is important to escape characters to prevent user input from being interpreted as code and potentially causing harm to the application or exposing sensitive information. 

// Example of using mysqli_real_escape_string to escape characters in a SQL query
$mysqli = new mysqli("localhost", "username", "password", "database");

// Check connection
if ($mysqli->connect_error) {
    die("Connection failed: " . $mysqli->connect_error);
}

// Escape user input to prevent SQL injection
$username = mysqli_real_escape_string($mysqli, $_POST['username']);
$password = mysqli_real_escape_string($mysqli, $_POST['password']);

// Query to insert user input into database
$query = "INSERT INTO users (username, password) VALUES ('$username', '$password')";
$mysqli->query($query);

// Close connection
$mysqli->close();

Keywords

escaping characters PHP security vulnerability SQL injection XSS attack

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