Pdo

How SQL Injection happens in PHP PDO queries and how to fix it

A critical SQL injection vulnerability was discovered in the `getOfficialContests()` method of ContestRepository.php, where the `$site_id` parameter was directly interpolated into a SQL query string instead of using prepared statements. This vulnerability allowed attackers to inject arbitrary SQL commands and potentially access or manipulate the entire contest database. The fix replaced `pdo->query()` with `pdo->prepare()` and proper parameter binding.