Coldcard Mk3 warning follows $38M Bitcoin drain

Coinkite warned Coldcard Mk3 users on July 30 to move Bitcoin from wallets whose seed phrases were generated on affected firmware. Summary 594 BTC moved across 500 transactions during a coordinated three-block sweep involving single-signature Bitcoin addresses. Coldcard Mk3 seeds generated on firmware 4.0.1 through 5.0.3 may face risk, Coinkite warned users. No public evidence yet links the Mk3 seed issue directly to the 594 BTC sweep. The Canadian hardware maker said seeds created on firmware 4.0.1 or any later Mk3 release through version 5.0.3 may put funds at risk. The notice arrived as security researchers examined a coordinated sweep of 594.48 BTC, worth about $38.2 million at a Bitcoin price near $64,324. However, Coinkite and independent researchers have not established that the Mk3 issue caused those transfers. Coldcard Mk3 warning covers firmware since 4.0.1 Coinkite’s official advisory said its investigation remains active. The company said the Coldcard Mk4, Q and Mk5 are not affected based on its early analysis. It also said wallets using an affected seed with a BIP-39 passphrase face “minimal risk,” while stressing that a passphrase is different from the device PIN. The...