Base has officially confirmed that a sequencer bug caused both mainnet outages on June 25 and 26, marking the first major incident since the network's launch. According to Base's latest postmortem, an invalid transaction failed during execution, but the critical issue occurred when stale journal state remained inside the block builder after the failed transaction. This stale state included accounts and storage slots touched by the failed transaction, causing the system to use incorrect journal state when processing valid transactions. The bug created an invalid state transition block that other nodes could not accept, effectively stopping block production and causing the chain halt. Base emphasized that "the integrity of the chain was not compromised and all funds on Base were safe" during both incidents.
Base has postponed its Beryl mainnet upgrade to June 26 at 18:00 UTC from the previously scheduled June 25 launch. According to reports from basedocs, the Ethereum layer 2 network attributed the delay to a timing dependency involving the B20 Activation Registry, which must complete its initialization before developers can deploy native B20 tokens. The network explained that the Activation Registry controls whether B20 feature flags become available after the hard fork, with the registry taking up to one hour to come online after activation, making the additional delay necessary before the upgrade proceeds. Developers cannot deploy the flagship B20 native token standard onchain until this Activation Registry is fully operational, a step that can take up to one hour after Beryl's activation.
Base successfully fixed the main sequencer bug by applying a patch that ensures journal state updates properly during execution after failed transactions. However, the team encountered a second issue during recovery when a race condition in the engine reset feature stopped sequencers from catching up after restart. This second problem affected sequencers specifically, not validator nodes, but it still slowed recovery efforts. The network's status page showed sequencing resumed on June 25, and ecosystem node operators were instructed to restart Base nodes if they remained stuck. During the outages, transactions queued in the mempool while the chain waited for block production to recover, with the transaction pool growing beyond storage capacity and causing eth_sendRawTransaction requests to return errors.
Beryl introduces B20, a protocol level token standard that allows issuers to create stablecoins and real-world asset tokens directly within Base's node software instead of deploying conventional ERC 20 smart contracts. As reported by basedocs, the hard fork also shortens the standard withdrawal period from Base to Ethereum from seven days to five days for the route used by most bridging providers. Base previously stated that B20 remains compatible with the ERC 20 specification and supports ERC 2612 permit functionality, allowing existing wallets, exchanges, and indexers to work without modification. The protocol includes an Issuer Toolkit offering role-based permissions, mint and burn controls, transfer restrictions, optional supply limits, and freeze and seizure features for regulated issuers.
Base has announced comprehensive measures to prevent future sequencer incidents, including strengthened protocol fuzz testing and load testing to detect strange transaction patterns that may expose hidden bugs. The team plans better monitoring and operational checks to help engineers detect similar problems earlier and respond faster. Base also wants to add graceful recovery to base-consensus, which would make it easier for validator nodes to continue syncing after similar failures. The outage occurred during a busy week for the network, which holds about $4 billion in deposits according to DefiLlama. Base has scheduled its next network upgrade, Cobalt for September, with plans to introduce native account abstraction, protocol level smart accounts, and additional B20 capabilities.
