Cybersecurity information sharing is a key factor of cyber threat intelligence, allowing organizations to detect and prevent malicious behaviors proactively. However, stimulating organizations to participate and deterring free-riding in such sharing is a big challenge. To this end, the sharing system should be equipped with a rewarding and participation-fees allocation mechanisms to encourage sharing behavior. The problem of cybersecurity information sharing as a non-cooperative game has been studied extensively. In contrast, in this paper, we model such a problem as a coalitional game. We investigate a rewarding and participation-fees calculation based on profit sharing in coalitional game theory. In particular, we formulate a coalitional game between organizations and analyze the well-known Shapley value and Nucleolus solution concepts in the cybersecurity information sharing system. Moreover, as the participation-fees may leak sensitive information about the organizations' cyber-infrastructure, we study the application of differential privacy in the coalitional game theory to protect the organization's fees while approximating the fairness.