Coldcard hardware wallet breach leads to $112 million Bitcoin theft

A major security breach involving Coldcard hardware wallets has resulted in the theft of over 1,778 Bitcoins, valued at approximately $112 million. The exploit targeted more than 5,000 wallets, with hackers managing to steal over 1,000 BTC in just 41 minutes on July 30, 2026.

The vulnerability is attributed to a flaw in firmware version 4.0.1, released by Coinkite in March 2021. The bug caused the devices—specifically the Mk2, Mk3, Mk4, Q, and Mk5 models—to generate predictable seed phrases rather than using a secure hardware random number generator. This flaw allowed attackers to compromise the private keys necessary to access individual cryptocurrency holdings.

While Coinkite issued a security advisory and a patch on the day the attacks began, the incident has raised significant concerns regarding the security of hardware-based storage. Experts suggest the breach highlights the importance of multi-signature setups and rigorous firmware integrity checks, as the issue lies in the software and key generation process rather than the Bitcoin protocol itself.