This Draft Recommendation provides a classification of security issues for the Internet of Things based on the impact vector of a probable attack, examines the security threats that may affect the functional safety of cyber-physical systems, and describes how security capabilities defined in Recommendation ITU-T Y.2068 support safe execution of cyber-physical systems in the Internet of Things. The Appendix of this Draft Recommendation considers how the joint analysis of threats and security capabilities mentioned herein may be used to establish requirements for protection mechanisms.