Severity: HIGH

Summary

Affected Code

class TOTPRateLimiter:
  def  init (self, ...):
    self.attempts: Dict[str, List[datetime]] = defaultdict(list)
    self.lockouts: Dict[str, datetime] = {}

class TOTPService:
   rate limiter = TOTPRateLimiter() # Class variable, in-memory only

Impact

1. Rate limit state is not shared across multiple server instances/workers — an attacker can distribute attempts
2. All rate limit state is lost on server restart — allows immediate retry
3. In multi-worker deployments, each worker has independent rate limit state

Recommended Fix

• Use Redis or the database for rate limit state storage
• Or use a shared-memory approach for multi-worker deployments
• At minimum, persist lockout state to survive restarts

Fix