**Vulnerability:** The Telegram Deployment Bot (`scripts/telegram_deploy_bot.py`) contained a "Fail Open" vulnerability where omitting the `TELEGRAM_ALLOWED_USER_IDS` environment variable resulted in granting access to *all* Telegram users instead of *none*.
**Learning:** Security controls must default to deny (Fail Closed). Implicitly allowing access when configuration is missing creates silent vulnerabilities that are hard to detect until exploited.
**Prevention:** Ensure all authorization checks explicitly return `False` or throw an exception if the access control list is empty or undefined. Never default to `True` in security-critical paths.
**Vulnerability:** The web dashboard (`scripts/web_dashboard.py`) caught exceptions and returned the raw error string to the user, potentially exposing sensitive internal details (paths, stack traces, database info).
**Learning:** Defaulting to returning `str(e)` in web handlers is a common pattern for debugging but dangerous in production. It violates the principle of failing securely.
**Prevention:** Always catch exceptions at the top level of request handlers, log the full details to a secure server-side log (e.g., `stderr`), and return a generic "Internal Server Error" message to the client.
