GHSA-22P3-QRH9-CX32 URL previews of unusual or maliciously-crafted pages can crash Synapse media repositories or Synapse monoliths

Impact URL previews of some web pages can exhaust the available stack space for the Synapse process due to unbounded recursion. This is sometimes recoverable and leads to an error for the request causing the problem, but in other cases the Synapse process may crash altogether. It is possible to...