Coldcard halts shipments amid multi-wave BTC theft

TLDR

Coldcard Bitcoin hardware wallets are facing a major multi?wave exploit that has stolen tens of thousands of BTC and led the company to halt shipments and destroy vulnerable units.

1. Attackers have exploited a flaw in Coldcard wallets across multiple waves, draining roughly 1,300 to 1,800 BTC (about 88 to 114 million dollars) from thousands of addresses.
2. The root cause is a firmware randomness bug dating to March 2021 that makes seeds guessable, putting certain Coldcard models and seeds generated on affected firmware at direct risk.
3. Recovery odds are seen as low and the exploit is still unfolding, raising questions about hardware wallet trust and prompting urgent security reviews across the self?custody ecosystem.

Deep Dive

1. Scale Of The Exploit

Onchain analysis and media reports link the Coldcard incident to at least 1,367 BTC stolen from 4,585 addresses, with some estimates climbing above 1,800 BTC and 114 million dollars as a fourth attack wave hits (Coinspeaker, The Defiant).

Galaxy Research and other analysts have documented multiple coordinated waves in which dormant Coldcard?generated addresses are swept within minutes, often in tightly batched transactions that match a distinctive pattern of vulnerable outputs (Daily Hodl).

Coldcards maker Coinkite has confirmed the vulnerability, halted new shipments, and destroyed remaining units with affected firmware in its facilities while contacting customers and law enforcement (Yahoo Finance).

2. Firmware Flaw And Who Is At Risk

The exploit is not phishing and does not require physical access. A pseudo?random number generator bug introduced in March 2021 caused some Coldcard firmware versions to rely on weak software entropy instead of the hardware random generator, collapsing seed strength and making private keys brute?forceable (Coinspeaker).

Reports indicate seeds generated on affected Mk3, Mk4, Mk5 and Q devices after that date are exposed if they relied on the flawed RNG, with patched firmware only protecting newly generated seeds. Older seeds cannot be retroactively secured and are expected to be drained over time unless funds are moved away (CryptoPotato).

Coinkite and independent researchers note that seeds created with strong extra entropy, such as extensive dice rolls or robust passphrases, and some multisig setups are less exposed, although many still recommend migrating to fresh, secure seeds (The Defiant).

3. Recovery Odds And Wider Impact

Onchain analyst Willy Woo has estimated only about a 20 to 40 percent chance that stolen Coldcard Bitcoin is ever partially recovered, warning that any legal recovery process could take years (Yahoo Finance).

Researchers have handed hundreds of suspected attacker addresses to authorities, but attackers have already begun using more obfuscated patterns such as unique destination wallets per victim, complicating tracing (The Defiant).

Industry voices argue that self?custody remains valuable but this incident exposes how hard it is for most users to independently verify hardware security, likely pushing some holders toward exchanges, ETFs, or diversified setups rather than relying on a single device vendor (TradingView / The Block).

Conclusion

The Coldcard exploit shows that even air?gapped hardware wallets can fail catastrophically when seed generation entropy is broken, leading to multi?wave thefts across thousands of addresses.

As investigations and further waves play out, the most important link is between firmware design, verifiable randomness, and user trust in self?custody. Watching how Coldcard, other wallet vendors, and regulators respond will shape hardware wallet standards and Bitcoin security assumptions going forward.