Coldcard users are being urged to migrate their seeds to new wallets immediately after an estimated $88.6 million in Bitcoin was drained from 4,585 addresses. According to Galaxy Research, three suspected attack waves removed 1,367.05 BTC from affected users. The warning was issued by Dogecoin community contributor Mishaboar, who advised users not to reuse their existing Coldcard seed phrase or enter recovery words into an internet-connected computer.
Affected Devices
The issue affects seeds generated on Mk2 and Mk3 devices running firmware versions 4.0.1 through 4.1.9, as well as seeds created on Mk4 and Mk5 devices before standard version 5.6.0 or Edge version 6.6.0X. Coinkite has released fixed firmware for every affected model and release track, which corrects the seed-generation process for new wallets.
Migration Process
Affected users should install the correct fixed firmware before generating a replacement seed. Coinkite advises recording and verifying the new backup, checking a receiving address on the device screen, and sending a small test transaction. Users should move the remaining balance only after confirming that the test funds reached the new wallet.
Security Measures
Mishaboar separately warned users never to type a seed phrase into a computer and recommended keeping offline copies in separate secure locations. A strong, unique BIP-39 passphrase creates an additional barrier, but Coinkite said it does not repair an affected seed.
