Flow validators deploy fix, prepare for network restoration after security breach

Key Takeaways

• Flow blockchain validators implement a protocol fix following a security breach.
• Approximately $3.9 million in assets were siphoned off due to a vulnerability in Flow’s execution layer.

Flow blockchain is moving toward a full restart after shipping a protocol fix tied to an exploit that drained approximately $3.9 million via cross-chain bridges, according to a new update from the team.

UPDATE: VALIDATOR CONSENSUS REACHED (MAINNET 28)

To preserve network integrity and prioritize user safety, the Flow Foundation proposed a protocol fix (Mainnet 28) which has been accepted and successfully deployed by network validators.

CURRENT STATUS: IDLE / READ-ONLY
The…

— Flow.com (@flow_blockchain) December 28, 2025

The incident occurred on December 27, targeting a vulnerability in its execution layer. The attacker moved assets off-network primarily through bridges to Ethereum before validators halted the network shortly, preventing further unauthorized transactions.

According to the Flow Foundation, the vulnerability has been isolated, law enforcement is engaged, and user funds held before the incident remain intact.

Validators have restored the network to a pre-exploit checkpoint and brought it back online in read-only mode while ecosystem partners synchronize systems. Transactions remain paused pending final coordination.

Once the coordination is complete, the network is expected to reopen. A full technical post-mortem remains scheduled for within 72 hours.

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