…While outages typically stem from a software failure, hardware issue or cyber attack, Euronext cited a “middleware” issue for the crash that halted trading in Paris, Brussels, Amsterdam, Lisbon and Dublin.

“To use an analogy, the pilot used to have a dashboard and a joystick that moved the rudder but now there is a middle bit where the joystick sends instructions into a computer before the rudder gets moved,” said Niki Beattie, founder at Market Structure Partners. “When middleware goes wrong it is like the joystick falling off.”…