MoneyMon (LegendaryMoneyMonNft) — ecrecover address(0) Signature Bypass

Timeline: On 29 May 2026, an attacker drained ~$85,519.47 (in USDT) from the LegendaryMoneyMonNft contract on BNB Smart Chain via a signature-verification bypass. The contract's verify() function returned recoverSigner(...) == admin, and recoverSigner used ecrecover without rejecting the address(0) return case; separately, changeadmin() allowed setting admin to the zero address. The attacker set admin to address(0), then submitted an invalid signature (r=0, s=0, v=27), which ecrecover reduces to address(0), so the == admin check passed. With authorization bypassed, the attacker called the (misspelled) cliamRewred function to arbitrarily claim and drain all reward tokens from the contract (0x92d60629...e5b6), swapping them for ~85,519.47 USDT on PancakeSwap. SlowMist detected and publicised the incident the same day. Recovery: 0%.