Coldcard vulnerability triggers 98% surge in Bitcoin's 7-day hot supply

Odaily Planet Daily reports that Vetle Lunde, Head of Research at K33, stated that the Coldcard attack likely triggered the movement of approximately 890,000 BTC within seven days, setting a new seven-day active supply record for 2026. K33 estimates that, as of the report’s preparation, around 7,300 addresses had already lost approximately 1,596 BTC. The incident stems from a firmware flaw introduced by Coinkite in March 2021 for the Coldcard hardware wallet, which may have generated wallet seeds with insufficient randomness. Since July 30, coordinated transfers have moved approximately 1,600 BTC—valued at over $100 million—from thousands of addresses, with a potential fourth wave of attacks bringing the total close to 2,000 BTC. On-chain data shows that Bitcoin’s seven-day hot supply rose from 403,101.95 BTC on July 28 to 797,407.72 BTC on August 4, an increase of approximately 394,306 BTC—a 98% surge. Sani from Timechainindex.com noted that since Friday’s Coldcard hack, exchanges have seen a net inflow of 22,052 BTC. Between July 30 and August 5, 39 dormant addresses transferred a total of 1,486.09044782 BTC, worth over $95 million. One address created in 2010 moved 50 BTC, while five addresses created in 2013 collectively moved 620.00100547 BTC.