What Is the Risk of a Re-Org to a Centralized Cryptocurrency Exchange?
A re-org poses a significant risk to exchanges that credit user deposits after a low number of block confirmations. If a deposit transaction is included in a block that is later reorganized out of the chain, the exchange's record of the deposit becomes invalid.
The user essentially gets their deposited funds back on the new chain while having already been credited on the exchange, leading to a loss for the exchange.