Nearly 200,000 XRP drained from Coreum cross-chain bridge exploit

The Coreum cross-chain bridge connecting to the XRP Ledger got gutted on August 9, losing approximately 199,916 XRP in under two hours. The bridge’s balance dropped from roughly 200,410 XRP to a lonely 493.5 XRP. The exploit didn’t involve a breach of XRPL itself or the theft of any private keys. Instead, the attacker found a flaw in the bridge’s relayer logic that treated fake deposit actions as the real thing, triggering legitimate XRP withdrawals from the bridge’s wallet on the other side. How the attack worked Cross-chain bridges hold assets on one chain and issue equivalent tokens on another. The Coreum bridge used a multisig relayer system, where a group of relayer nodes collectively authorize transactions, to manage this process between XRPL and Coreum’s ecosystem. The vulnerability lived in the deposit verification process. The bridge’s relayer logic was supposed to confirm that deposits on one chain were genuine before authorizing withdrawals on another. The attacker was able to submit fabricated deposit actions that the system accepted as legitimate, which then triggered real XRP payouts from the bridge’s XRPL wallet. On-chain analysis showed 94 multisig-authorized paymen...