Universe is in danger?

Well, yes and no. The standard model of current physics contains a vacuum that isn't entirely stable and should disintegrate over time. According to the latest calculations, the vacuum in which we live isn't stable but it's sufficiently stable for the universe to disintegrate at a rate of 10 raised to 500 years.

The vacuum for physicists means the absence of particles but not the absence of all things. Quantum physics indicates that space is filled with objects that we call fields and we get to see the particles when these fields receive energy and move the particles from one place to another in space.

Particles would be the manifestation of something more fundamental that fills all of space, even when there are no particles those fields are still there. So vacuum would be what the fields do when they're not busy moving particles from one side to the other.

A classic example of this would be taking two metal plates and place them in a vacuum chamber facing each other. Between the plates there's emptiness because they're inside a vacuum chamber and outside there's also emptiness but the point here is that we would be talking about different emptiness.

The vacuum between the plates has less energy than the one outside and when this experiment is performed, the two plates come closer to each other spontaneously, without external action. This is interpreted as the vacuum from outside pushing the vacuum between the plates, because it has more energy. This is called the Casimir effect.