Hack history / 2026 / Hack or exploit
COLDCARD
Hack or exploit on Jul 31, 2026 · Weak Key Generation
SOURCES DISAGREE ON DATE OR LOSS · 4 SOURCES
Lost
$116M
sources: $100M to $130M
Returned
none listed
as the sources state it
Rank
#49
among thefts by dollars lost
What happened
Starting 30 July 2026 attackers drained BTC in four waves from thousands of addresses whose seeds were generated on Coldcard hardware wallets running firmware 4.0.0+ (March 2021 onward), where a firmware bug bypassed the dedicated hardware RNG during key generation, cutting effective key strength to as little as 40 bits and allowing offline brute-forcing.
Details
- Date
- Jul 31, 2026
- Kind
- Hack or exploit
- Method
- Weak Key Generation
- How in
- Keys, accounts and infrastructure
- Target
- Wallet
- Chains
- Bitcoin
Related incidents
Cite this page
SwanBluechip, "COLDCARD hack, Jul 31, 2026: $116M lost", Crypto hack history, https://swan-hack-tracker.pages.dev/history/i/ht65c6843bfd/ (data as of 2026-11-01).