Coldcard Firmware Bug Exposes Users to $130M in Stolen Bitcoin

A critical firmware bug in Coldcard wallets has led to over $130 million in Bitcoin stolen from unsuspecting users. The issue, which affected older models running firmware versions 4.0.1 through 4.1.9, was caused by a build flag that disabled the hardware random number generator.

The bug effectively reduced the search space for private keys from 128 bits to around 40, making it easier for attackers to guess the keys and gain access to the funds.

Galaxy Research has tracked over $130 million in stolen Bitcoin across three confirmed waves, with a suspected fourth wave bringing the total to around $2 billion. Coinkite, the manufacturer of Coldcard wallets, has issued a technical backgrounder explaining the issue and has since released fixed firmware for affected models.

Experts warn that users who generated seeds using the compromised firmware should regenerate their seeds and move their funds to avoid further losses.