A composite pressure container for fluids includes a pressure container, a boss (1), and a coupling or valve member (5) fitted in an opening in the boss. The pressure container includes an inner fluid-tight liner layer (4) and a pressure supporting layer (3) formed by winding fiber-reinforcement onto the liner layer. The boss is positioned in a central opening of the pressure container. The structure of the boss comprises a depressurization passage for preventing build-up of internal pressure inside the boss.