Coldcard’s Entropy Bug Exposed a Hidden Weakness in Hardware Wallet Security
The whole point of a hardware wallet is that it's unreachable.
The private keys never touch the internet. The device never connects to anything except the moment you plug it in to sign a transaction. An attacker who can't physically hold the device in their hands is, in theory, locked out forever. That's the pitch. That's why people buy them. That's why serious Bitcoin holders — people with real money, long-term holders who hadn't moved their coins in years — chose Coldcard specifically. It had a reputation as the most security-focused hardware wallet on the market.
On July 30, 2026, an attacker drained $89 million from 4,585 of those wallets. In three waves. Without touching a single device.
The flaw wasn't in the cryptography. It wasn't a smart contract exploit or a phishing attack or an exchange getting compromised. It was a one-line code change, made on March 1, 2021,...
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