MARA Foundation says its Slipstream service is now open to anyone, with no signup code required, at the same moment thousands of bitcoin holders are racing to move funds off a flawed hardware wallet.
Key Takeaways
MARA Foundation opened Slipstream to the public on August 3, 2026, dropping its client code requirement.A Coldcard firmware flaw from March 2021 let hackers drain up to $88 million from about 500 wallets.Watch for updated Coldcard firmware guidance and further loss estimates as more addresses are checked.Most bitcoin transactions travel through a shared waiting room called the mempool, where every node on the network can see a transaction before it gets confirmed into a block. Slipstream skips that waiting room. A user submits a signed transaction directly to MARA, and it stays hidden until MARA mines a block with it inside.
“MARA Slipstream is now available as a permissionless public good with no client code requirement. Please be careful and conservative with fees to avoid transactions getting stuck in the Slipstream mempool in the event that competitive rates spike. For the foreseeable future, we are not charging additional fees for this service, but users are responsible for paying appropriate Bitcoin transaction fees.”
That last point matters. MARA is not adding its own surcharge. Users still pay normal Bitcoin network fees, they just send the transaction through a private channel instead of the open one.
A Hardware Wallet Flaw Forces the Timing Hackers Race to Drain Weak WalletsA firmware patch stops new wallets from inheriting the flaw, but it does nothing for seed phrases already generated under the broken code. Anyone who set up a Coldcard during the affected years has to move their coins to a new wallet.
Moving Funds Publicly Creates Its Own TrapMARA’s Slipstream removes that window of exposure. Because the transaction never touches the public mempool, an attacker never sees the keys or the spending details until MARA has already mined the coins into a confirmed block.
Slipstream Predates the Crisis by Two Years Users Still Carry the Trust and Timing RiskSlipstream still depends on MARA finding blocks. A transaction sits in MARA’s private queue until the pool mines one, so timing depends entirely on MARA’s share of Bitcoin’s total hashrate.
Watch for updated loss estimates as more compromised addresses surface, additional guidance from Coldcard on which firmware versions and serial ranges are affected, and whether other miners follow MARA in offering a similar private submission path.
