Are there wormholes in black holes?
This is an open topic of research.
Essentially the idea is that a rotating black hole cannot collapse to a point singularity since a point cannot have angular momentum. As a result, such spinning black holes may have a flat disc shaped singularity of zero thickness, which could function as a sort of wormhole, allowing objects falling into the black hole to avoid the central point singularity and potentially traverse the wormhole.
It is not clear whether such a geometry would be stable and this is an active area of research.