CVE-2020-7057
Hikvision DVR DS-7204HGHI-F1 V4.0.1 build 180903 Web Version sends a different response for failed ISAPI/Security/sessionLogin/capabilities login attempts depending on whether the user account exists, which might make it easier to enumerate users. However, only about 4 or 5 failed logins are allowed.
Source: CVE-2020-7057