Binance hot wallet signed 50 EIP-7702 delegations 3 minutes before the drain

On 29 October 2026, Binance’s Ethereum hot wallet signed 50 EIP-7702 authorizations delegating execution to a newly deployed contract. A separate transaction carried those signatures onto the chain; three minutes later, the contract used one valid authorization to drain 167,464 ETH and 63 tokens, including 1.615 billion USDT, worth an estimated $2.5-2.8 billion. The authorizations covered 50 consecutive wallet nonces because the heavily used wallet’s nonce kept advancing. By execution, 34 signatures were stale, 15 remained unused, and one enabled the sweep. Earlier tests with smaller nonce windows suggest the attacker had rehearsed the method. The crucial security issue is that an authorization is only 29 bytes and lacks the ordinary transaction fields - such as destination, amount, and call data - that signing policies commonly inspect.

Related withdrawals on XRP, Solana, Bitcoin, and other networks sent funds to newly created addresses, while Binance 14 alone used EIP-7702. That pattern supports two competing explanations: an attacker had the private keys, or compromised access to Binance’s signing pipeline produced signatures the system’s rules failed to recognize as dangerous. Binance’s initial account attributed the incident to a compromised DevOps laptop and service container, with no evidence that wallet keys had leaked; if accurate, the attacker induced the signing service to authorize the requests. The chain cannot resolve which explanation is correct. The security lesson is that wallet policies must identify and separately govern EIP-7702 authorizations, including the contract they delegate to, rather than relying only on checks designed for conventional transactions.