Monero Nodes Experience 18-Block Reorganization

Monero (XMR), the privacy-centered coin, has recently experienced a significant event in its network. According to reports, Monero suffered an 18-block reorganization, in which 117 to 118 transactions were invalidated over about 40 minutes. 

Notably, this unusual incident has raised concerns, particularly about the effects of outside hashrate and the security of the network.

Understanding the 18-Block Reorganization

A blockchain reorganization occurs when a longer chain overtakes the current main chain, leading to the removal or replacement of confirmed blocks. 

Recently, Monero nodes had an 18-block deep reorg. This is a significant change and led to nearly 120 transactions being invalid. It is worth noting that a reorg can disrupt network agreement and temporarily weaken transaction finality.

Undoubtedly, an 18-block reorganization in the blockchain is rare. This incident has sparked discussions in the Monero community, especially about the distribution of mining power outside the known Qubic mining pool. 

Likewise, some community members believe that external mining groups have impacted the reorganization by using excess hash power, which caused the network to become unstable. 

However, these claims are not verified, and no one has been definitively blamed. While block reorganizations can happen due to network latency or competing miners, an 18-block reorg is uncommon and raises questions about potential underlying causes.

The Monero 51% Attack

Last month, cryptocurrency exchange Kraken ended XMR deposits on its platform. The company made this decision after discovering 51% attacks on the token’s blockchain.  The 51% attack happens when one mining pool gains control of more than 50% of a blockchain network’s total hashing power.

This empowers such a mining pool with the ability to double-spend and reorder transactions on the ledger. Apart from reversing transactions, the single mining pool in control could also block new ones.

Qubic Takes Over 51% of Monero Blockchain

In Monero’s case, Kraken claims that its action is only a precautionary measure, especially as the current state of the mining pool “poses a potential risk to network integrity.” However, Kraken’s announcement had no notable impact on the XMR price at the time of reporting.

Layer-1 AI-focused blockchain and mining pool Qubic has claimed responsibility for the majority of Monero’s hashrate. In other words, it is the single mining pool with major control over the blockchain. So far, it has reordered six blocks, a move that prompted denials of the attack from the Monero community.