- Use $wpdb->prepare() with esc_like() in clear_article_cache()
- Add strict base64_decode() validation with error handling
- Add isset()/is_array()/is_string() checks for nested array access
- Add wp_http_validate_url() SSRF prevention on all image downloads
- Add limit_response_size (5MB) on image URL downloads
- Set chmod 0644 after file_put_contents()