HomeBox is a home inventory and organization system. Prior to 0.27.0, the POST /api/v1/users/login endpoint performs password-hash verification only when the submitted username matches an existing account, while unknown usernames return immediately. Although both paths return the same 401 unauthorized response, the processing-time discrepancy allows an unauthenticated remote attacker to distinguish registered email addresses; rate limiting only reduces the number of attempts per window. This issue is fixed in version 0.27.0.