Coldcard Exploit Sends $90M of Bitcoin Back to Exchanges

A firmware flaw in the Coldcard hardware wallet has caused a sudden influx of $90 million worth of Bitcoin into exchanges.

Wind to Exchanges: Record Daily Deposits

■Daily transfers under 10 BTC spiked to 7,300 BTC, the highest since February 6, 2024.

■Daily active addresses surged from 645,000 to almost 1,000,000, a peak last seen on December 10, 2024.

■Net inflows totaled 11,163 BTC, funneling into major exchanges: Binance, OKX, Kraken, and River.

Seed Phrase Breach: Why the Hack?

Coldcard’s March 2021 firmware bug caused devices to fall back on a software RNG instead of the hardware RNG, reducing entropy and allowing offline reconstruction of seed phrases.

■The flaw led to 1,000–1,300 BTC lost (roughly $70–90 million).

■Over 1,000 addresses were affected, with the largest bursts occurring in under an hour.

Investor Response: Crypto Ecosystem’s Sensitivity

■After the FTX collapse, investors moved to self‑custody; the Coldcard incident has reversed that trend, sending funds back to exchanges.

■Binance founder CZ and other key figures are reassessing hardware wallet security.

■Total exchange‑held Bitcoin rose to 2.715 million BTC from 2.703.837 million BTC.

Solutions and Precautions: New Hardware Wallet Security Paradigm

■Coinkite released a firmware update; users are urged to replace older units with the latest firmware.

■Most hardware wallets and properly generated seeds remain secure; the incident was a single manufacturer’s error.

■The crypto ecosystem is moving toward stricter self‑custody standards.

The crypto market demonstrates how security incidents can shift investor behavior. Large transfers into exchanges may boost short‑term liquidity, but underscore the need for rigorous RNG standards and firmware updates in hardware wallets. Investors should treat RNG quality and update practices as critical criteria when choosing self‑custody solutions.