A sequencer bug was accountable for two outages of the Coinbase layer-2 community Base final week, based on a autopsy.
The Base engineering crew stated in a Saturday autopsy that they recognized a bug in sequencer block-building logic that allowed “stale journal state” to persist after a transaction validation failure.
“An invalid transaction was obtained by the block builder and failed throughout execution, as anticipated, however erroneously didn’t clear the journal state that contained the accounts and storage slots that had been accessed,” stated the crew.
The Base layer-2 community runs a single sequencer, which implies one bug can cease all the things. It’s a centralized blockchain element that decides the order of transactions and has been accountable for outages on different layer-2 chains, together with Arbitrum, OP Mainnet and zkSync Period.
On Thursday and Friday, Base mainnet skilled two block manufacturing outages, the primary incident lasted 116 minutes and the second lasted 20 minutes.
There was an entire halt of latest layer-2 blocks, and the sequencer and validator nodes couldn’t progress previous the invalid block till sequencing was restored.
The crew fastened the outages by making use of a patch to the sequencers to make sure the journal state was correctly up to date throughout execution.
Nevertheless, mitigation took longer than anticipated “because of infrastructure situations unrelated to the unique bug,” they stated.
There was additionally a “race situation” after the system reset, which prevented the sequencers from catching up, inflicting the second outage.
Associated: Coinbase’s Base resumes block manufacturing after 2-hour outage
Going ahead, the Base engineering crew plans to enhance protocol “fuzz testing,” which entails bombarding the system with giant volumes of random, malformed, or sudden inputs to search out bugs, and constructing “swish restoration” in order that validator nodes don’t want guide restarts throughout future incidents.
Not the primary outage for Base
It isn’t the primary sequencer-related outage for Base, which stopped producing blocks for 17 minutes in September 2024 and for round half an hour in August 2025.
Base is the second-largest layer-2 community by complete worth secured, which is just below $11 billion, in accordance to L2beat.
Journal: AI is banking the unbanked in Africa… quicker than crypto