Café Bitcoin | Coldcard Emergency: What Happened, Who's Affected, and What To Do Now

The event. A firmware flaw in Coldcard seed generation, disclosed the night before, let an attacker recompute private keys outright. By airtime, 594 Bitcoin, put at roughly $38 million on the show, had been swept from about 500 wallets. The mechanism. Yan Pritzker and Swan engineer Steve: the device's true random number generator was present and working, but a March 2021 library change meant the firmware silently stopped using it, falling back to software randomness seeded from device ID and clock. Why five years passed. The code looked correctly wired, the failure hinged on a build-time variable, and the output still looked random. Zach Herbert of Foundation said a researcher flagged something adjacent in 2022 without unraveling it. Who is exposed. Only seeds the Coldcard generated itself. Imported seeds are safe, dice rolls are safe, a long passphrase saved people. MK3 is worst hit. MK4, MK5 and Q sit near 72 bits, costly to attack but not impossible. Updating firmware does not fix it. Coinkite patched, including MK3, but the vulnerable seed is the problem, not the device. You must generate a new seed and move funds. The dice function was never affected and has now been audited. Multisig is not automatically safe. If most keys came from affected devices, an attacker can try permutations, and spending publishes your public keys and invites an RBF race. Wicked pointed people to Portland.HODL for private broadcast through Slipstream. The attacker looks unsophisticated. The sweep ran roughly 25 minutes into a handful of addresses, stopped at shallow address gaps, and queried a public node instead of running one. Block researchers identified that service, so there may be a lead. The industry reckoning. American HODL called it a Paul Revere moment and demanded podcasters and former sponsors broadcast immediately. Reardon argued the industry spent three years arguing over the wrong priorities and got caught by an entropy bug. Self-custody versus diversification. Wicked held that multi-vendor multisig with your own entropy beats any custodian. Joe Carlasare countered that every system rests on assumptions that eventually fail. Yan declined to preach one model, calling self-custody still very early. Swan's status and the scam wave. Yan confirmed Swan Vault is built on Blockstream Jade and unaffected, and reported an influx of deposits. He flagged a devious scam variant where attackers send you working seed words and ask you to deposit into them.