Security alert · Coldcard hardware wallet

Move your Bitcoin off any Coldcard seed created since March 2021 — today.

A firmware bug made affected Coldcards generate seed phrases with a predictable software RNG instead of the chip's hardware RNG. Attackers have already reconstructed the private keys offline and drained more than 1,778 BTC across three confirmed waves, without ever touching a device — and a suspected fourth wave remains unconfirmed. Updating the firmware does not repair a seed that already exists. If your seed was generated on a Coldcard on or after March 2021, treat it as compromised: move the coins now to a new seed on patched firmware, to a different hardware wallet, or — if you need somewhere immediately — to an exchange you already use, and sort out longer-term custody after the coins are safe.

Watch for follow-on scams. Events like this draw fake “migration” and “wallet checker” sites. Coinkite will never ask for your seed words, and no legitimate tool needs them. Type coldcard.com in by hand rather than following links from social media or email.

Am I affected? Version list and migration steps

The flaw cut seed randomness from the intended 128 bits to roughly 40 bits on Mk2/Mk3 and 72 bits on Mk4/Mk5/Q. Your seed is at risk if you generated it on the device while running:

  • Mk2 / Mk3 — 4.0.1 through 4.1.9
  • Mk4 / Mk5 — anything before 5.6.0 (standard) or 6.6.0X (Edge)
  • Q — anything before 1.5.0Q (standard) or 6.6.0QX (Edge)

Two exceptions. Coinkite states seeds are not at risk from this bug if you supplied at least 50 fair, independent rolls through Add Dice Rolls and those rolls were never recorded or exposed. Seeds generated before firmware 4.0.1 (March 2021) are also outside the affected range. If you are not certain which applies to you, assume you are affected and move the coins.

Current status. Galaxy Research has recorded no confirmed attacker activity since Aug 6, 2026. It reads that pause as vulnerable holders having already moved or been drained rather than as a fix — the underlying method still works, and Galaxy still tells single-signature Coldcard holders to move their funds. Should sweeping resume, note that some earlier attacker transactions had replace-by-fee enabled: if you find an unconfirmed transaction spending from your address sitting in the mempool, you may have a short window to broadcast your own higher-fee transaction and move the coins first.

Migration. Update the firmware, generate a brand-new seed, verify the backup and a receive address, send a test transaction, then move the remaining funds. Keep the old backup until the migration is confirmed.

Independent tracing by Galaxy Research attributes at least 1,778 BTC (about $112M) drained across three confirmed waves, as of Aug 14, 2026 — up from 1,719 BTC on Aug 7. A suspected but still unconfirmed fourth wave of roughly 638 BTC would raise the total to about 2,417 BTC (~$151M) across more than 7,700 addresses. Around 1,531 BTC of the stolen coins still sits unmoved in attacker-controlled addresses; none has been recovered. Bitcoin Lending Intel is not affiliated with Coinkite and this is not financial advice. Verify firmware versions and guidance against Coinkite's own advisory before acting.
Comparison Updated 2 Jul 2026

Strike vs Unchained: which is better for a Bitcoin loan?

Two Bitcoin-first lenders we rate lower-risk — but they sit at opposite ends of the cost-versus-control trade-off. Strike is cheap, fee-free and custodial; Unchained is pricier but lets you keep a key to your own collateral. Here's how they compare, from each lender's own verified terms.

The short version Both cap Bitcoin loans at 50% LTV and both are Bitcoin-focused lenders we rate lower-risk. Strike is the cheaper, simpler borrow — fixed-rate 12-month loans from ~9.5% APR with no origination fee and a $10,000 minimum — but it holds your Bitcoin in segregated custody. Unchained costs more (~14–16% plus ~2%) and starts at ~$150,000, but your BTC stays in a 2-of-3 multisig vault where you hold a key. Choose Strike for lowest cost and easy access; Unchained if keeping control of a key is worth the premium and you're borrowing large.

Side by side

 StrikeUnchained
Headline APRFrom ~9.5%~14–16%
Max LTV50%50%
Liquidation LTV~85%~83%
Term12 months12 months
FeesNo origination fee~2% origination
Custody modelSegregated custody (custodial)Collaborative multisig — you hold a key; no rehypothecation possible
CollateralNative BTCNative BTC
Minimum loan$10,000~$150,000
Best forLowest cost, mid-sized loansLarge / HNW borrowers who want key control
Our risk tierLowerLower

Strike's rate varies by loan type (Payment-at-Maturity prices higher than Monthly) and size, with no published upper bound; the comparison uses its ~9.5% starting APR. Figures reflect each lender's published terms as of the date above — always confirm at the source. See full data and source links in the comparison table.

The real difference: who holds your Bitcoin

Strike is a custodial lender. It holds your Bitcoin in segregated custody — kept separate rather than pooled — but the company still controls the collateral, so you're trusting Strike and its custodian to hold and return it. In exchange you get simple, cheap, fixed-rate loans.

Unchained is built to remove that trust requirement. Your Bitcoin goes into a 2-of-3 collaborative multisig vault where you hold one of the keys. Unchained can't move, lend out, or rehypothecate your collateral without your signature, and if the company failed your keys and BTC would remain under your control. That's the premium you're paying for — not a better rate, but a fundamentally different custody risk.

Rates & cost

Strike wins on cost, clearly. Its fixed-rate 12-month loans start around 9.5% APR with no origination fee, though the rate rises with loan type and size and has no published ceiling. Unchained runs roughly 14–16% APR plus about a 2% fee. For a comparable loan, Strike is materially cheaper and simpler on fees — you'd choose Unchained despite the higher cost, not because of it.

Access & loan size

Strike's $10,000 minimum makes it realistic for a broad range of borrowers. Unchained's ~$150,000 minimum targets high-net-worth individuals and businesses. If you're borrowing a mid-sized amount, Unchained may not be available to you at all, which often settles the decision before rate or custody even enter the picture.

Who each is best for

Choose Strike if…

  • You want the lowest cost and no origination fee
  • You're borrowing from about $10,000 upward
  • A transparent, segregated custodial model is acceptable to you

Choose Unchained if…

  • You want to keep control of a key and rule out rehypothecation
  • You're borrowing at a large scale (~$150K+)
  • You'll pay a higher rate and fee to avoid trusting a custodian

FAQ

Is Strike or Unchained cheaper?

Strike — its fixed-rate loans start around 9.5% APR with no origination fee, versus Unchained's ~14–16% plus about 2%. Unchained's premium buys its keep-your-keys custody, not lower pricing.

What's the difference in custody?

Strike holds your Bitcoin in segregated custody (custodial). Unchained uses 2-of-3 collaborative multisig where you hold a key, so your collateral can't be moved or rehypothecated without your signature.

Can I get a mid-sized loan from either?

From Strike, yes — its minimum is about $10,000. Unchained's minimum is roughly $150,000, so it targets large and business borrowers.

Do they take my actual Bitcoin?

Both use native BTC as collateral, not a wrapped token, so there's no taxable conversion. The difference is whether the company holds it (Strike) or you co-hold keys to it (Unchained).

See how Strike and Unchained compare to everyone else

Rate, LTV, liquidation level, custody and fees for every lender we track — independently verified, with a source link on every row.

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