In CentOS-WebPanel.com (aka CWP) CentOS Web Panel 0.9.8.848, the Login process allows attackers to check whether a username is valid by comparing response times.
packetstormsecurity.com/files/154164/CentOS-Control-Web-Panel-CWP-0.9.8.848-User-Enumeration.html
packetstormsecurity.com/files/154164/CentOS-WebPanel.com-CentOS-Control-Web-Panel-CWP-0.9.8.848-User-Enumeration.html
packetstormsecurity.com/files/154164/CentOS-WebPanel.com-Control-Web-Panel-CWP-0.9.8.848-User-Enumeration.html