An integer underflow vulnerability in the dnsproxyd component of the PAN-OS management interface allows authenticated administrators to issue a command from the command line interface that causes the component to stop responding. Repeated attempts to send this request result in denial of service to all PAN-OS services by restarting the device and putting it into maintenance mode. This issue impacts: PAN-OS 9.1 versions earlier than PAN-OS 9.1.3. This issue does not impact PAN-OS 8.1, PAN-OS 9.0, or Prisma Access services.