A heat exchanger for cooling a flow of media, comprising a plurality of pipes. The pipes are each received in a respective pipe base at the ends, and the pipes are received in a housing between the two pipe bases, the housing being connected to the pipe bases in a fluid-tight manner. A coolant channel is formed by a shaped region oriented outwards along an outer wall which delimits the housing. The coolant channel has an opening oriented in the direction of the inner volume of the housing, and the coolant channel is in fluidic communication with the inner volume of the housing via the opening. The opening is at least partly covered by a panel, and the panel is arranged on the housing outer wall surface oriented inwards, the outer wall having the coolant channel. A gap is formed between an edge, which delimits the opening, and the panel.