with the advent of new technologies and software, software industry is becoming more competitive. The users are pressurizing software developers to deploy a fully secured system. Software security under evolving requirements and continuous error detection, often leads to the development of several successive version of a system. Software products are growing more sophisticated, the writing of latest versions has become complex and time consuming activity. For software security reasons it is necessary to understand the nature of security and the best way to do it is to identify new security factors and analyze them. In this paper stability is discussed as a security factor of software security. Predicting software stability with enhanced new version is a key factor for software security Stability, like most security factor, is a complex phenomenon and its prediction is a real challenge.