The denial-of-service can be triggered by transmitting a carefully crafted CAN frame on the same CAN network as the vulnerable node. The frame must have a CAN ID matching an installed filter in the vulnerable node (this can easily be guessed based on CAN traffic analyses). The frame must contain the opposite RTR bit as what the filter installed in the vulnerable node contains (if the filter matches RTR frames, the frame must be a data frame or vice versa).

There is an error in the condition of the last if-statement in the function smpcheckkeys. It was rejecting current keys if all requirements were unmet.