A method performed by a core network node in a core network of a wireless communication system includes receiving a first request to establish a first protocol data unit, PDU, session between a user equipment, UE and a user plane function in the core network, generating user plane, UP, security enforcement information, to be applied to the first PDU session, transmitting the UP security enforcement information to a radio access network, RAN, node for establishing the first PDU session, and storing the UP security enforcement information for use in establishing a subsequent PDU session for the UE.