This Recommendation provides a security framework and requirements for open capabilities of telecommunication services. This Recommendation analyses the challenges brought forward by open capabilities of telecommunication services and identifies hence the specific security requirements for the operators. These security requirements specified together form a security framework for operators to manage the security of open capabilities of their telecommunication services. The purpose of this Recommendation is to safeguard operators' capabilities of telecommunication services and the business paradigm of open capabilities of telecommunication services, to protect operators' telecommunication systems and to enhance user experience.