Coldcard Deploys Major Firmware Upgrade Following Seed Attack Vulnerability

Coldcard has released a firmware upgrade to address a seed-generation vulnerability that exposed some customers to theft.

The company urges Mk4, Mk5, and Q users to install firmware 5.6.1, which changes how devices create, protect, and validate wallet data.

The update requires users to add randomness during seed creation, either by pressing keys, rolling dice, or flipping coins.

Coldcard combines this input with hardware entropy and cryptographic protections, but warns that the upgrade cannot protect seeds created through the vulnerable process.