The fastest thing in the universe is generally considered to be light, or more precisely, electromagnetic radiation. In a vacuum, light travels at a constant speed known as the speed of light, which is approximately 299,792 kilometers per second (or about 186,282 miles per second).
According to our current understanding of physics, nothing with mass can reach or exceed the speed of light. This is a fundamental principle of Einstein's theory of relativity, which has been extensively tested and confirmed by various experiments. As an object with mass accelerates towards the speed of light, its energy requirements increase infinitely, making it impossible to reach or exceed this speed.
Space itself, on the other hand, is not considered to have a "speed" in the same way that objects do. Space is the medium through which light and other objects move. It does not have a velocity or a maximum speed. Instead, it provides the framework within which objects and light propagate.
So, while light travels at the maximum speed in the universe, space itself does not possess a speed in the same sense. It is the medium that allows for the movement and propagation of objects and light, including the transmission of light itself.