Bitcoin SV (BSV), a fork of Bitcoin Cash, has been confirmed by crypto research firms CoinMetrics and SlowMist to have suffered a 51% attack, resulting in nearly 100 blockchain reorganizations and the simultaneous operation of three distinct blockchain versions.
A 51% attack occurs when an attacker gains temporary control over more than half of a blockchain's total mining hash rate. This allows them to reverse transactions, double-spend coins, and disrupt network consensus. For users, this means losing control over their assets, ultimately eroding trust in the affected cryptocurrency.
How the Bitcoin SV 51% Attack Unfolded
Lucas Nuzzi from CoinMetrics was the first to detect the attack via their FARUM risk-management platform. Initial attempts failed, but the attacker eventually succeeded in causing a 12-block reorganization, with three blockchain versions running in parallel.
CoinMetrics later confirmed that despite only one successful attack, mining pools were thrown into chaos, triggering a 14-block deep reorganization.
"All of our FARUM nodes witnessed a deep reorg with a max depth of 14 blocks. No further reorganization events have been witnessed, but synchronization conflicts persist on major mining pools."
— CoinMetrics (Tweet)
Nikita Zhavoronkov, a developer at Blockchair, reported that BSV actually experienced a 100-block reorganization, invalidating 570,000 transactions over nearly 10 hours.
Bitcoin Association Urges Node Updates
The Bitcoin Association, which supports BSV, issued a call to miners and node operators to run a specific command and invalidate the attacker's chain:
"To invalidate the fraudulent chain, node operators should run:bitcoin-cli invalidateblock 000000000000000003B67AEC95E9B5DA897EB5EBF3227D5A6A67835104367840
Please reach out on Twitter with any questions."
— Bitcoin Association (Tweet)
However, the association’s response and the attack itself drew sharp criticism from the Bitcoin community.
Community Backlash: "Is BSV Run via Twitter?"
Cobra, the operator of Bitcoin.org (which previously lost a legal battle to Craig Wright over hosting the Bitcoin whitepaper), mocked BSV, calling its consensus mechanism "Proof-of-Social-Media (PoSM)":
"The Bitcoin Association is now running the blockchain via Twitter. Should miners check tweets regularly to maintain consensus? BSV is achieving higher throughput with patented triple-chain technology."
— Cobra (Tweet)
Others pointed out that after the Bitcoin Association’s command, the three competing BSV chains would race to invalidate each other, exacerbating network instability.
👉 Learn how to protect your crypto from 51% attacks
FAQs About the BSV 51% Attack
Q: What is a 51% attack?
A: It’s when an attacker gains majority hash power to manipulate transactions, potentially causing double-spending and chain reorganizations.
Q: How did the BSV attack happen?
A: The attacker forced deep reorganizations (up to 100 blocks), creating three competing chains and invalidating thousands of transactions.
Q: Can BSV recover?
A: The Bitcoin Association’s invalidation command may help, but the attack has already damaged trust in BSV’s security.
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Risk Warning:
Cryptocurrency investments are high-risk, with volatile prices that may lead to total capital loss. Assess risks carefully.
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