A control device comprising a processor, wherein the processor is configured to: acquire a warning level indicating a warning measure related to an abnormality that has occurred in a vehicle, from a device installed externally to the vehicle; detect an abnormality that has occurred in the vehicle, from equipment mounted to the vehicle; perform thinning control on a detection result of the abnormality detected according to the warning level; and transmit the detection result resulting from thinning to the device.