What are the potential risks or security concerns when reading variables passed via POST from external sources in PHP?

When reading variables passed via POST from external sources in PHP, there is a risk of injection attacks, such as SQL injection or cross-site scripting (XSS). To mitigate these risks, it is important to sanitize and validate the input data before using it in your application. 

// Sanitize and validate input data from POST
$username = isset($_POST['username']) ? htmlspecialchars($_POST['username']) : '';
$password = isset($_POST['password']) ? htmlspecialchars($_POST['password']) : '';

// Use the sanitized input data in your application
// For example, you can now safely use $username and $password in database queries or other operations

Keywords

SQL injection cross-site scripting data validation input sanitization secure coding practices

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