Runtipi is a personal homeserver orchestrator. Prior to 4.8.1, The Runtipi /api/auth/verify-totp endpoint does not enforce any rate limiting, attempt counting, or account lockout mechanism. An attacker who has obtained a user's valid credentials (via phishing, credential stuffing, or data breach) can brute-force the 6-digit TOTP code to completely bypass two-factor authentication.

The TOTP verification session persists for 24 hours (default cache TTL), providing an excessive window during which the full 1,000,000-code keyspace (000000-999999) can be exhausted. At practical request rates (~500 req/s), the attack completes in approximately 33 minutes in the worst case. This vulnerability is fixed in 4.8.1.