What are potential pitfalls of automatically parsing the content of PHP files for BBCode?

Automatically parsing the content of PHP files for BBCode can lead to security vulnerabilities if the input is not properly sanitized. To solve this issue, it is important to thoroughly validate and sanitize the input before parsing it for BBCode to prevent any potential malicious code execution.

// Example of validating and sanitizing input before parsing for BBCode
$input = $_POST['content'];

// Validate and sanitize input
$clean_input = filter_var($input, FILTER_SANITIZE_STRING);

// Parse the sanitized input for BBCode
$bb_parsed_content = parseBBCode($clean_input);

// Function to parse BBCode
function parseBBCode($content) {
    // Implement BBCode parsing logic here
    return $parsed_content;
}