- Coinkite warns that COLDCARD Mk3 firmware versions 4.0.1 to 5.0.3 may have vulnerable wallet seeds, putting Bitcoin at risk.
- The issue does not affect COLDCARD Mk4, Mk5, or Q devices; users with a BIP-39 passphrase face minimal risk.
- Users are urged to migrate to a new seed generated on unaffected hardware, verifying backups and testing transfers before moving large balances.
- Coinkite is investigating and will release a detailed technical analysis; experienced users may use a dice-roll method to avoid the Mk3's random-number generator.