ELECTRICAL SYSTEM,SERVICE BRAKESSummary: Unintended full brake engagement at highway speeds caused by electronic parking brake/Auto Hold button defect. Extreme risk of collision. Details: On [XXX], my wife was driving our 2023 Kia Forte GT Line when the Auto Hold and electronic parking brake system malfunctioned. The system fully engaged the brakes without warning while traveling at highway speed, scraping the brake rotors and creating an immediate risk of being rear-ended. This occurred multiple times. The following day ([XXX], the brake pedal would not depress at all, rendering the vehicle undrivable. The dealership (McFarland Kia, North Hampton, NH) diagnosed “a sticky substance” inside the electronic parking brake button, located next to the cupholder. There have never been any liquid spills in this vehicle. The more likely cause is a combination of factory lubrication and normal dust/debris accumulation over time. If such a small amount of dust or residue can trigger unintended full braking while driving, it is a dangerous design flaw that poses a life-threatening hazard to drivers and passengers. The vehicle was repaired after I paid $284.99 out-of-pocket, but I am pursuing reimbursement through my Zurich Vehicle Service Contract. I have also requested an independent third-party brake and rotor inspection, as this defect may have caused further damage. Why this is a safety issue: Sudden, uncommanded braking at highway speeds can cause high-speed rear-end collisions. The defect can occur without visible warning and without any driver action. The defect can be triggered by minimal non-liquid debris, which is unavoidable over the life of a vehicle. I am requesting NHTSA investigate whether this is an isolated case or part of a larger design defect in the Kia Forte’s electronic parking brake/Auto Hold system. This condition should not be possible in a vehicle that meets federal safety standards. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)