THORChain halts 10 chains after Ethereum reorg, 10 ETH shortfall
6.6 Security THORChain paused trading on 10 blockchains after an Ethereum reorg caused a 10 ETH overpayment. The issue was quickly detected and resolved, but trading remains paused on several chains.
THORChain halted trading across 10 blockchain networks after an Ethereum one-block reorganization on October 31 led to a 10 ETH deposit being both credited and refunded, despite the funds never reaching the vault. The deposit was included in a block that was later dropped from Ethereum’s canonical chain, but THORChain had already processed it, resulting in an accounting shortfall. The protocol’s automated solvency checker detected the discrepancy and halted ETH swaps within minutes. Node operators then paused trading on the affected chains as a precaution. The user who received the extra 10 ETH returned the funds, restoring the vault’s balance. This incident exposed a vulnerability in cross-chain transaction verification, as external chain reorganizations could enable double-counting or replay attacks. Trading remains suspended on Bitcoin, Ethereum, Solana, Tron, BNB Smart Chain, Cosmos, Bitcoin Cash, Dogecoin, Litecoin, and Zcash, while AVAX, BASE, RUNE, and XRPL continue operating. The disruption also slowed the movement of assets linked to the Binance hack through THORChain.
