Can Hardware Wallets Be Hacked? What the Coldcard Hack Reveals

Hardware wallets are widely considered one of the safest ways to store Bitcoin and other cryptocurrencies. By keeping private keys away from internet-connected devices, they reduce exposure to malware, exchange breaches and many common online attacks.

But can hardware wallets be hacked?

Yes, hardware wallets can be hacked or compromised. They are generally more secure than hot wallets, but they are not invulnerable. Attackers may exploit firmware bugs, predictable seed generation, counterfeit devices, malicious software, physical access or mistakes made by the wallet owner.

The 2026 Coldcard hack provided a striking example. Bitcoin was stolen from wallets whose owners believed their keys were securely stored offline. This is clear proof that a hardware wallet’s security depends on more than whether the device connects to the internet.

A hardware wallet does not physically store cryptocurrency. Bitcoin and other digital assets remain recorded on their respective blockchains.

The device instead protects the private keys needed to authorize transactions. When a user sends crypto, the transaction is signed inside the hardware wallet so that the private key should never need to enter an internet-connected computer.

Examples of Coldcard hardware wallets

Coldcard, for example, is a Bitcoin-only hardware wallet that offers air-gapped transaction signing, secure elements and verifiable firmware. These protections are designed to isolate private keys and reduce the number of ways an attacker can reach them. 

The Coldcard incident was linked to a firmware flaw affecting the process used to generate wallet recovery phrases.

According to security researchers, a firmware integration error that was introduced in March 2021 caused certain Coldcard devices to use a deterministic software pseudorandom number generator instead of relying properly on the device’s hardware random number generator. 

Under specific conditions, an attacker could reproduce possible outputs, derive candidate seed phrases and compare the resulting addresses with public Bitcoin blockchain data. The attackers did not necessarily need to steal a device, connect to it remotely or obtain its recovery phrase through phishing. They could recreate vulnerable private keys on their own computers.

By Aug. 4, 2026, Galaxy Research confirmed that approximately 1,596 BTC had been stolen from about 7,300 addresses across three major attack waves and 14 smaller incidents. The confirmed losses exceeded $100 million.

A hardware wallet is still a computer running software. A mistake in its firmware can affect seed generation, transaction verification, PIN protection or communication with other devices.

The Coldcard incident sheds some light on how a single flaw in a random-number-generation process could undermine wallets that otherwise remained offline.

Firmware updates may stop a device from creating additional vulnerable wallets. However, updating the firmware does not automatically repair a recovery phrase that was generated with weak randomness. Funds must be transferred to a new wallet created with a securely generated seed.

A recovery phrase should be generated from enough randomness that guessing it is practically impossible.

Example of secret recovery phrase

When poor randomness produces seeds from a much smaller range of possibilities, attackers can test those possibilities until they find addresses holding funds. This is especially dangerous because Bitcoin addresses and balances are publicly visible.

In this type of attack, the recovery phrase does not need to be extracted from the wallet. The attacker recreates it.

Many supposed hardware wallet “hacks” occur when users voluntarily enter their recovery phrases into fake websites, applications or support forms.

A legitimate wallet provider should never ask a user to submit a recovery phrase online. The phrase should not be photographed, entered into cloud storage, saved in a password manager or typed on an internet-connected computer. Anyone who obtains it can recreate the wallet and spend its funds.

Attackers can also distribute fake hardware wallets or tamper with genuine devices before they reach buyers.

In one 2026 example, a counterfeit Ledger device directed its owner to malicious software designed to collect seed phrases and other sensitive information. The fake device closely resembled an authentic product, but the official Ledger software identified it as non-genuine. 

Always buy directly from the manufacturer or an authorized reseller to reduce this risk. A device that arrives with a recovery phrase already written down should never be used.

A hardware wallet cannot protect users who approve a transaction they do not understand.

Malicious applications may create transactions that send funds to an attacker, grant extensive token permissions or interact with dangerous smart contracts. Users should verify the destination address, amount and transaction details on the hardware wallet’s own screen before approving anything.

Some attacks require possession of the device and specialized laboratory equipment. Researchers have revealed techniques like voltage glitching, laser fault injection and side-channel analysis against different wallet models.

These attacks are generally less practical than phishing or firmware exploitation, but they show why a stolen hardware wallet should still be treated as a security incident.

No. An air gap reduces the opportunities for remote malware to communicate directly with the wallet, but it does not eliminate every risk.

An air-gapped device may still:

• Generate a weak recovery phrase.
• Run vulnerable or malicious firmware.
• Receive a manipulated transaction through a QR code or memory card.
• Display an address that the user fails to verify.
• Be compromised before delivery.
• Be accessed by someone who knows the PIN.
• Depend on a recovery phrase that has already been exposed.

The Coldcard hack is particularly important because the affected wallets did not need to be online. If an attacker could predict the seed, the physical device was no longer necessary.

Hardware wallets are still a strong security option when correctly manufactured, audited, configured and used. The Coldcard incident does not prove that self-custody is inherently unsafe, but it does show that no single device should be treated as automatically trustworthy.

Exchange custody introduces a different collection of risks, including platform hacks, insolvency, account freezes and withdrawal restrictions. Self-custody removes some of those risks while also making the owner responsible for device security, backups and transaction verification.

For larger holdings, security should be designed as a system rather than based on one product.

Users can reduce the risk of a hardware wallet compromise by taking several precautions:

1. Purchase from an official source: Avoid unknown marketplaces and second-hand devices.
2. Generate the recovery phrase on the device: Never use a phrase supplied in the packaging or by a seller.
3. Keep firmware updated: Download updates only from the manufacturer’s official website and verify them when supported.
4. Follow security advisories: When a seed-generation vulnerability is announced, moving funds to a new seed may be necessary. A firmware update alone may not secure existing keys.
5. Never enter the seed phrase online: Do not type it into websites, computers, chatbots, support forms or mobile applications unless performing a legitimate recovery through a trusted wallet interface.
6. Verify transactions on the device: Check the complete receiving address and amount before signing.
7. Use a strong passphrase carefully: A sufficiently strong BIP39 passphrase may add another layer of protection, but losing it makes the wallet unrecoverable. Weak passphrases may still be brute-forced.
8. Consider multisignature security: A properly designed multisig wallet can require keys from multiple independent devices. Using several devices with the same vulnerability, however, may reproduce the same point of failure.
9. Separate devices and backups: Do not keep a wallet and its recovery phrase in the same location. Coinkite’s guidance recommends geographically separating backups and testing wallet recovery before depositing significant funds. Storing everything under one seed creates a single point of failure. Separating funds across independently generated wallets can limit the damage caused by one compromised key.

Can someone hack a hardware wallet remotely?

It is possible, although direct remote access is not the only threat. An attacker may exploit weak seed generation, compromised companion software or malicious transactions without establishing a normal connection to the wallet.

Can a hardware wallet be hacked without the device?

Yes. The Coldcard incident showed how attackers may derive private keys if a wallet generated a predictable seed. Anyone who obtains or recreates the seed can control the funds without possessing the original device.

Can crypto be stolen if a hardware wallet is offline?

Yes. Cryptocurrency remains on the blockchain rather than inside the device. If an attacker obtains the corresponding private key or recovery phrase, the funds can be transferred from another wallet.

Does updating firmware protect an existing wallet?

It depends on the vulnerability. An update can fix the software that creates new wallets, but it cannot change an existing recovery phrase. When seed generation has been compromised, users normally need to create a new seed and transfer their funds.

Is a hardware wallet safer than an exchange?

A hardware wallet removes reliance on an exchange and protects keys from many online attacks. However, it places responsibility for backups, updates and transaction verification on the owner. Neither method is completely risk-free.