The development team behind Coinbase’s Ethereum Layer-2 network Base has released a detailed post-mortem explaining the technical issues that triggered two consecutive network outages last week. According to the report, a software bug inside the blockchain’s sequencer caused block production to stop, while an additional synchronization issue delayed the network’s full recovery.
Following an extensive internal investigation, Base engineers confirmed that both service interruptions originated from a flaw in the sequencer’s block-building logic. The unexpected bug allowed outdated journal data to remain in memory after an invalid transaction failed during execution, ultimately preventing the blockchain from continuing normal operations.
The engineering team explained that the incident began when the sequencer received an invalid transaction. Although the transaction itself was correctly rejected during validation, the system failed to clear temporary journal data that tracked accessed accounts and storage information. This stale internal state remained active instead of being discarded, creating inconsistencies that prevented the sequencer from successfully producing new blocks.
Because Base currently relies on a single centralized sequencer to organize and process transactions before they are finalized on Ethereum, any critical software failure within this component can temporarily halt the entire network. Once the bug was triggered, both the sequencer and validator nodes became unable to advance beyond the invalid block, effectively freezing blockchain activity until engineers implemented a fix.
The first outage interrupted block production for approximately 116 minutes, while a second incident shortly afterward lasted around 20 minutes. During both events, users were temporarily unable to process transactions, interact with decentralized applications, or receive confirmations on the Base network.
To restore operations, developers deployed an emergency software patch designed to ensure that journal data is correctly cleared whenever transaction execution fails. The update successfully resolved the underlying software bug and allowed block production to resume.
However, engineers revealed that restoring the blockchain took longer than initially expected because additional infrastructure-related issues complicated the recovery process.
After the initial system reset, Base encountered a separate race condition, a type of software timing error that occurs when multiple processes attempt to perform operations simultaneously before previous tasks have completed. This synchronization problem prevented sequencer nodes from catching up with the latest blockchain state, ultimately triggering the second outage before normal operations were fully restored.
The engineering team emphasized that this secondary issue was unrelated to the original bug but nevertheless contributed to the extended recovery timeline.
To reduce the likelihood of similar incidents in the future, Base plans to introduce several improvements to its development and testing procedures.
One of the primary initiatives involves expanding protocol fuzz testing, a software testing technique that continuously feeds systems with large volumes of random, malformed, and unexpected inputs to uncover hidden bugs before code is deployed into production. By exposing the network to a broader range of abnormal scenarios during testing, developers hope to identify potential vulnerabilities much earlier in the development cycle.
In addition, the team intends to strengthen the blockchain’s recovery mechanisms by implementing more automated failover procedures. These enhancements should allow validator nodes to recover automatically after unexpected interruptions without requiring manual intervention from network operators, significantly reducing downtime during future incidents.
The latest disruption is not the first time Base has experienced sequencer-related reliability challenges. The Layer-2 network previously suffered a 17-minute outage in September 2024, followed by another interruption lasting approximately 30 minutes in August 2025. While those incidents were resolved relatively quickly, they highlighted the operational risks associated with centralized sequencing infrastructure.
Despite these occasional outages, Base remains one of the largest Layer-2 ecosystems built on Ethereum. The network currently secures nearly $11 billion in total value locked (TVL), making it the second-largest Ethereum Layer-2 platform by total value secured. Its continued growth has been driven by expanding activity across decentralized finance (DeFi), blockchain gaming, tokenized assets, and Web3 applications.
As adoption of Layer-2 scaling solutions continues to accelerate, infrastructure reliability is becoming increasingly important for both developers and institutional users. Base’s transparent disclosure of the incident and its planned technical improvements demonstrate the team’s commitment to strengthening network resilience, improving software quality, and minimizing the risk of future service disruptions as the ecosystem continues to expand.