Home›Crypto›Regulation›Coldcard firmware upgrade forces users to replace vuln…

Coldcard firmware upgrade forces users to replace vulnerable seeds

The update, released by Coinkite for multiple Coldcard models, requires new seeds to be generated with at least 65 keypresses or other user-controlled entropy and says existing phrases remain vulnerable after upgrading.

Reported · Written up by our desk · Regulation

Coinkite has released firmware updates for Coldcard hardware wallets that strengthen seed phrase generation, but it also warns users that any existing seed phrases created with previously vulnerable entropy remain unsafe even after the upgrade.

In a Thursday blog post, the company said firmware 5.6.1 is available for Coldcard Mk4 and Mk5, and version 1.5.1Q is available for the Coldcard Q. The updates require newly generated seeds to include user-supplied entropy, using methods such as at least 65 keypresses with unpredictable timing, 50 six-sided die rolls, or 128 coin flips, which are then mixed with improved device randomness from secure elements and the hardware RNG.

Coinkite directed users to upgrade immediately and replace existing seed phrases with newly generated ones before migrating funds. It also described the goal as keeping private keys unpredictable even if one of the device’s entropy sources fails, and said the new release adds additional safeguards around USB data handling, transaction signing, and hardware randomness.

The update comes after confirmed losses from the Coldcard exploit reached 1,778 Bitcoin, worth about $112 million, according to a Galaxy Research report dated Aug. 14. The incident has been ranked as the third-largest cryptocurrency exploit of 2026, based on data aggregated by DefiLlama.

Latest closeBitcoin $77,298.59 ▲5.8%

More like this

Sources