What is the potential issue with variable passing through URLs in PHP?

When passing variables through URLs in PHP, there is a potential security risk known as "URL injection" where malicious users can manipulate the variables to perform unauthorized actions or access sensitive information. To prevent this, it is recommended to sanitize and validate any variables passed through URLs before using them in your code. This can be done by using functions like htmlspecialchars() to escape special characters and filter_input() to validate input. 

// Sanitize and validate variable passed through URL
$variable = filter_input(INPUT_GET, 'variable', FILTER_SANITIZE_STRING);

// Use the sanitized variable in your code
echo "Variable passed through URL: " . $variable;

Keywords

security vulnerability URL parameters data leakage injection attacks server-side validation

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