An attacker exploited Chainflip’s TRON-specific swap instruction and refund handling. Unlike Chainflip’s other integrations, TRON swap instructions were derived from transaction memos. The attacker could attach a different memo to a transaction already signed by Chainflip validators, causing Chainflip to interpret the transaction as another swap. When that duplicate instruction failed, the protocol refunded it even though the underlying deposit had already produced a payout, effectively allowing the same deposit to be paid twice. The attacker attempted the sequence eight times over approximately 90 minutes, with six unauthorized payouts succeeding