Base Network Outage Review: Root Cause of Consecutive Downtime is a Sequencer Program Vulnerability

Jinse Finance reports that on June 28, according to official sources, the root cause of two consecutive outages on Coinbase's Layer 2 network Base last week has been confirmed as a software bug in the block construction logic of the Sequencer.

The Base engineering team stated that after an invalid transaction failed to execute, the associated temporary state (Journal State) should have been cleared, but due to a program defect, the old state was incorrectly retained, ultimately preventing the Sequencer and validator nodes from continuing to generate new blocks. On June 26, the Base mainnet experienced two block production interruptions, the first lasting 116 minutes and the second lasting 20 minutes.

The team noted that although the sequencer state update issue was fixed with a patch, a "race condition" occurred after the system reboot, causing the sequencer to fail to resume synchronization in time, leading to the second outage. Additionally, some infrastructure issues prolonged the overall recovery time.

Base stated that it will intensify protocol fuzz testing in the future to enhance vulnerability detection under abnormal input scenarios, and optimize the network recovery mechanism to avoid future incidents requiring manual restart of validator nodes.

It is worth noting that this is not the first time Base has experienced a failure due to Sequencer-related issues; it suffered network outages of approximately 17 minutes and 30 minutes in September 2024 and August 2025, respectively. Currently, Base remains the second-largest Ethereum Layer 2 network by total value locked (TVS).