Consensus Finality Mismatch

Consensus finality mismatch describes the danger arising when two blockchains operate under different rules for determining when a transaction is irreversible. Some chains provide probabilistic finality, where the probability of a transaction being reversed decreases over time, while others offer deterministic finality, where a transaction is final once included in a block.

When a bridge relies on a source chain that has not yet reached absolute finality, it may process a transfer that is later reorganized or invalidated by the source chain. This creates a state discrepancy where the destination chain reflects an asset transfer that effectively never happened on the source.

Such mismatches can be exploited to double-spend assets or cause liquidity providers to suffer significant losses. Protocols must implement deep confirmation requirements to bridge this gap, though this often results in slower transaction speeds.

This risk is a core challenge in ensuring the integrity of cross-chain financial settlement.