Vitalik warned about cross-chain bridge risk just a few weeks ago:

My argument for why the future will be multi-chain, but it will not be cross-chain: there are fundamental limits to the security of bridges that hop across multiple "zones of sovereignty".

Note that cross-rollup apps within one zone of sovereignty are still fine. Not also that this also is a limit to the "modular blockchains" vision: you can't just pick and choose a separate data layer and security layer. Your data layer must be your security layer.

https://twitter.com/vitalikbuterin/status/147950136619213209...