Bridging / L2 Risks
With the rise of the NFT hype in 2021, especially on the Ethereum blockchain, this led to rising gas fees, low transactions speeds and an overall congestion of the blockchain never seen before. Thus, not only alternative blockchains like Solana or Avalanche had a meteoric rise by proclaiming high transaction volumes and low costs, but also so-called Layer 2 (L2s) solutions to the Ethereum blockchain (Layer 1) became popular. These L2s operate as sub-chains, allowing high transaction volume and low costs and settle the transaction in bulks (depending on the underlying technology) on the Ethereum main chain.
As more and more users wanted to move funds from the highly congested and thus expensive Layer 1 Ethereum chain, this created the necessity to build bridges from either one Layer 1 blockchain to another (like the Wormhole bridge between Ethereum and Solana) or L2 bridges like between Ethereum to Polygon.
As these bridges are build upon smart contracts, they again are vulnerable for hacks or exploits: