Connected and Automated Vehicles use sensors and wireless communication to improve road safety and efficiency. However, attackers may target Vehicle-to-Everything communication. Indeed, an attacker may send authenticated but wrong data to send false location information, alert incorrect events or report a bogus object endangering the safety of other CAVs. Currently, Standardization Development Organizations are working on developing security standards against such attacks. Unfortunately, current standardization efforts do not include misbehavior specifications for advanced V2X services such as Collective Perception yet. This work assesses the security of Collective Perception Messages and proposes inputs for consideration in existing standards.