The contact owns a 2023 Hyundai Palisade. The contact stated that while in stop-and-go traffic, the brake pedal was depressed and was abnormally stiff. As a result, the vehicle failed to come to a complete stop and crashed into another vehicle. The "Critical Forward Safety functions are limited" and "Radar blocked." warning messages were displayed on the instrument panel. The air bags did not deploy. A police report was filed and there were no injuries reported. A dealer was contacted and referred the contact to the manufacturer. The manufacturer was notified of the failure and informed the contact that a packet would be mailed and needed to be completed on the incident. The contact was then informed that based on the information in the packet, an investigator may reach out to the contact within six to eight weeks to inspect the vehicle. The vehicle was later taken to a dealer where an inspection was performed however the failure was not determined. The vehicle was not repaired. The contact related the failure to NHTSA Campaign Number: 23V415000(Service Brakes, Hydraulics). The failure mileage was approximately 3,550.