The amount of Bitcoin stolen in the Coldcard hack has climbed above $100 million. Researchers connected the affected addresses to recovery seeds generated by vulnerable Coldcard firmware. How the Coldcard Vulnerability WorkedThe Coldcard incident was not a compromise of the Bitcoin network itself. Wallet seed generation was moved from Coldcard’s hardware random-number generator to a function provided through the libNgU and MicroPython software stack. An attacker could generate potential seeds offline, derive their corresponding Bitcoin addresses and compare them with publicly visible addresses on the blockchain.