Coldcard Firmware Flaw Leads to $70M Bitcoin Theft

A significant firmware vulnerability in Coldcard hardware wallets allowed attackers to exploit weak seed generation, resulting in the theft of approximately 1,367 BTC (around $70 million) from nearly 1,200 wallets. The exploit occurred on July 30, 2026, when the attackers drained funds in a coordinated operation without needing physical access to the devices. The flaw stemmed from a failure in the random number generation process, which compromised the security of recovery seeds. Coinkite, the manufacturer of Coldcard, confirmed that affected devices included Mk3 models running firmware version 4.0.1 and later. Users were advised to generate new wallet seeds and transfer their funds to secure their assets. The incident has raised concerns about the security of hardware wallets and the effectiveness of current protective measures. As of August 2, 2026, the situation remains critical, with ongoing investigations into the extent of the theft and potential future risks.

Key Points: • Attackers exploited a firmware flaw in Coldcard wallets, draining $70 million in Bitcoin. • The vulnerability allowed the reconstruction of private keys from weak recovery seeds. • Affected users are advised to generate new wallet seeds and transfer funds immediately.