Bitcoin worth a total of 14 billion yen stolen in three waves of attacks exploiting a vulnerability in the hardware wallet “COLDCARD”

A random number generation flaw in the COLDCARD hardware wallet appears to have been exploited to drain bitcoin.

Three attacks since July 30, 2026 are estimated to have stolen a total of 1,082.65 BTC from 1,196 addresses.

The losses are valued at about 14 billion yen, highlighting how hardware wallet vulnerabilities can trigger large-scale asset theft.

The incident raises fresh concerns about user asset protection and product reliability.