The paper presents a context-aware environment-role-based access control model (CERBAC). Unlike traditional systems where access control has been explored, access decisions may depend on the context in which requests are made. It illustrated how the well-developed notion of roles can be used to capture security relevant context of the environment in which access requests are made. By introducing environment roles, a novel access control framework that incorporates context-based access control it creates. Moreover a architecture is presented that supports security policies that make use of environment roles to control access to resources. Furthermore, it outlines the configuration mechanism needed to apply our model to the Web services environment, and describes the implementation architecture for the system.