Wormholes are portals in space used by the Voids to travel to any system in the galaxy from their home system.
They are generated by the Void mothership, and no other species is known to be capable to master the necessary technology to create wormholes.
Before the invention of the Khador Drive, wormholes were the only way to access the Void space. However, because they changed their location in space, it was often difficult to reach them.
As you gets closer to a wormhole, you will notice that your ship will start to vibrate. If the Polytron Boost is used near a wormhole, due to the vibrations the aiming reticle just gets off the screen.
In the middle of the story, Keith T. Maxwell acquires a tool allowing to know in real time where the Void wormhole is in the galaxy, and so lend support to local security forces. After the Void mothership is destroyed by Erkkt Uggut, there are no wormholes anymore in the galaxy. Wormholes are more often than not found in the Pescal Inartu system.