What are common mistakes to avoid when passing variables through links in PHP?

Common mistakes to avoid when passing variables through links in PHP include not properly encoding the variables to prevent injection attacks and not validating the input to ensure it meets the expected format. To solve this issue, always sanitize and validate any user input before passing it through links to prevent security vulnerabilities. 

// Sanitize and validate input before passing it through links
$variable = filter_input(INPUT_GET, 'variable', FILTER_SANITIZE_STRING);

if ($variable) {
    // Encode the variable before passing it through links
    $encoded_variable = urlencode($variable);
    
    // Use the encoded variable in the link
    echo "<a href='example.php?variable=$encoded_variable'>Link</a>";
}

Keywords

PHP variable passing links security vulnerabilities URL parameters

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