Sequencer Bug Caused Two Base Network Outages in a Week

A post-mortem by the Base engineering team found a bug in sequencer block-building logic that allowed "stale journal state" to persist after a transaction validation failure. "An invalid transaction was received by the block builder and failed during execution, as expected, but erroneously did not clear the journal state that contained the accounts and storage slots that had been accessed," the team said.

Base runs a single sequencer, a centralized component that decides transaction ordering, so one bug can halt the network. On Thursday and Friday the mainnet stopped producing blocks twice: the first incident lasted 116 minutes and the second 20 minutes, with sequencer and validator nodes unable to progress past the invalid block until sequencing was restored.

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