Wozu ist dieser Schlauch am LuFi-Kasten? | Posts 16+

You can also seal the cut-off stub with two components of modeling clay (e.g., Petec Powerstahl) or with a screw. Attach a small inline filter to the vacuum hose, as shown in the middle of the picture. The picture on the right shows the same filter, but with the housing removed. This is not a paper filter, but one with a very fine mesh.
Alternatively, you can drill out the broken stub and glue a straight pipe connector using the putty or another suitable adhesive. Then, you can reattach the vacuum hose to the connector as usual.