Base mainnet suffered a chain stall on June 25 after a consensus problem allowed an invalid block to be sequenced, stopping new blocks after block 47806542. The outage disrupted mainnet block production, deposits, withdrawals and client software while engineers worked to recover sequencing and node synchronization.
The incident started at 16:03 UTC, when Base mainnet block production became unhealthy. The team later isolated a problematic block that interfered with subsequent block building, then recovered sequencing of new blocks by 17:51 UTC.
By 17:58 UTC, Base had recovered healthy blockbuilding and moved the incident into monitoring. Ecosystem-wide infrastructure was able to recover syncing, but Base told node runners that affected nodes would need to be restarted to recover synchronization.
Invalid Block Stopped New Blocks
The stall came from a consensus issue, not a confirmed exploit of user funds or a bridge-drain event. An invalid block entered the sequencing path, and the chain could not continue producing valid blocks after that point until the sequencer and internal nodes recovered.
For users and apps, the effect was direct. Transactions could not progress normally while block production was stalled, and deposits or withdrawals tied to Base mainnet were disrupted until blockbuilding recovered. Client software also showed partial outage conditions during the incident, creating additional recovery work for infrastructure operators and node runners.
The outage came as Base continues expanding beyond simple Layer 2 transfers into app infrastructure, payments and agent workflows. Recent Base development has included MCP integrations across trading, lending, NFTs, token launches and x402 payments, making uptime more important for apps that depend on continuous transaction flow.
Beryl Upgrade Still Moves Ahead
The chain stall landed on the same day as Base’s scheduled Beryl mainnet upgrade. Base said it expected the upgrade to activate as planned at 18:00 UTC, even after the earlier block-production incident moved into monitoring.
Beryl requires Base node operators to run version 1.1.1 or later of the base/base software. The upgrade window was scheduled for 18:00 to 20:00 UTC, adding a second infrastructure event to a day already shaped by the mainnet stall.
The incident also matters because Base has become a core rail for Coinbase-linked onchain products. Coinbase’s Bitcoin-backed borrowing stack already runs through Morpho markets on Base, with more than $2.17 billion in user loans tied to the same onchain credit infrastructure model.
Base mainnet blockbuilding has recovered, sequencing has resumed and the Beryl upgrade window is active. The unresolved part is the root-cause review around the invalid block, with Base still monitoring stability and preparing a full postmortem after the investigation concludes.
