Sui Mainnet Halts Three Times in 48 Hours Traced to Upgrade Bug, Developers Confirm

Key Highlights

• Sui’s mainnet experienced three separate halts within a 48-hour period on May 28–29, 2026
• The incidents were traced to a bug introduced in the v1.72 network upgrade
• The first two outages were linked to issues in gas-charging logic involving a new address-balance feature
• A third halt was triggered by a separate bug related to validator randomness-state during restarts
• The Sui Foundation says no user funds were lost and no transactions were reversed
• An emergency fix restored network activity after each interruption
• The events add renewed scrutiny to Sui’s network reliability and upgrade testing process

The Sui Foundation has confirmed that its blockchain mainnet suffered three separate outages over a 48-hour window, all of which were ultimately traced back to software issues introduced in the network’s recent v1.72 upgrade. The halts occurred on May 28 and May 29, 2026, temporarily stopping transaction processing and block production across the network.

According to the post-mortem, the first two outages were caused by a defect in how the upgraded system handled gas-charging logic, particularly when interacting with a newly introduced address-balance feature. Under certain edge conditions, transactions could trigger validator crashes, leading to a full network stall.

After the initial incident, developers deployed an emergency fix intended to restore functionality quickly. However, that workaround carried a known low-probability risk, which ultimately contributed to a second outage when the same edge case reappeared in network conditions.

The third outage, according to the foundation, was unrelated to the gas logic bug and instead stemmed from a separate issue involving how validator nodes preserved randomness-state during restarts and epoch transitions. This second bug was exposed during recovery operations, triggering another temporary halt.

Despite the repeated disruptions, the Sui Foundation emphasized that user funds were never at risk and no finalized transactions were rolled back. Once validators coordinated patches and restarted correctly, the network resumed normal operation.

The incidents have drawn attention because Sui is positioned as a high-performance Layer 1 blockchain competing on speed and scalability. Multiple halts in such a short period have raised questions among developers and investors about upgrade safety, testing rigor, and the resilience of complex protocol changes under real-world conditions.

The foundation has stated that both issues have now been addressed and that additional safeguards will be introduced to reduce the likelihood of similar failures during future upgrades.