Can bitcoin be hacked?

Whether bitcoin can be hacked depends on what you mean by bitcoin. The network, meaning its rules and the shared ledger, has never been broken in a way that let an attacker take coins from other wallets. The software that runs it has had serious bugs, and the people and companies holding bitcoin are hacked often.

Has bitcoin ever been hacked?

Bitcoin.org's FAQ says the protocol and its cryptography have worked since 2009, though security flaws have been found and fixed in software over time. It adds that thefts at exchanges and other businesses did not involve bitcoin itself being hacked.

The clearest example of a flaw came in 2018. Bitcoin Core disclosed a bug, tracked as CVE-2018-17144, that could crash nodes and, under some conditions, let a miner create extra coins by spending the same value twice. Fixed versions came out on September 18, 2018, and the developers said they knew of no attempt to exploit it.

What was the bitcoin value overflow bug of 2010?

On August 15, 2010, a transaction in block 74,638 created about 184.5 billion bitcoin across addresses, according to the Bitcoin Wiki. The code checking transactions did not handle output values so large that their sum overflowed.

Within about five hours, a fixed client was released that rejected such transactions. Miners switched to it, and by block 74,691 on August 16 the fixed chain was longer than the bad one. The fake coins no longer exist on the chain everyone uses today. It stands as the main case of the network briefly accepting something its rules were meant to forbid.

Can bitcoin be hacked by quantum computers?

Not today. A large future quantum computer could in theory work out private keys from public keys that are visible on the chain. Developers have drafted proposals to prepare, which our guide on whether quantum computers can break bitcoin covers in depth. A separate risk, an attacker controlling most mining power, is explained in what is a 51 percent attack.

How do people lose bitcoin to hackers?

Bitcoin.org says user error, such as lost or stolen wallet files, is the most common weakness. In practice, thieves go after keys and the businesses that hold them:

• Exchanges and custodians. The FBI attributed the theft of about 1.5 billion dollars in crypto from the exchange Bybit, in February 2025, to North Korea.
• Personal wallets. Chainalysis counted more than 158,000 thefts from individual wallets in 2025, affecting about 80,000 people, as reported by Finance Magnates.
• Scams and malware. Fake apps, phishing links and tricks that reveal a seed phrase.

The patterns behind these attacks are covered in how crypto gets hacked. Once bitcoin moves, the transfer is final, so protecting the private key is what keeps coins safe.