Coldcard Warns Users Over $38M Bitcoin Sweep Amid Security Concerns
Coinkite has issued a warning to Coldcard Mk3 users after a $38 million Bitcoin sweep raised security concerns. The issue affects recovery seeds generated using specific firmware versions, including those from v4.0.1 through v5.0.3.
The transfer of 594.48 BTC across 500 transactions took place within a three-block window, with around 562 BTC later consolidated into a single address. Initial observations suggest 'flawed entropy' during wallet generation, but no confirmed link has been established between the on-chain movement and the Coldcard Mk3 issue.
Coldcard Mk4, Mk5, and Coldcard Q users are not affected, nor are those with wallets protected by a BIP-39 passphrase. However, Coinkite recommends that affected users migrate their funds as a precaution while the investigation continues.