Sui Mainnet Restarts After Three Outages from 1.72 Bugs

Sui’s mainnet returned to normal operations after three separate outages on May 28 and May 29 that were traced to bugs introduced in the 1.72 software upgrade.

The first halt began about 7:00 a.m. PT on May 28 and lasted until roughly 1:30 p.m. PT. The 1.72 release added address balances as a way to pay transaction fees. When two transactions attempted to draw from the same address balance at the same time, one transaction was cancelled but the network still attempted to deduct its fee. That produced an impossible negative balance and caused validators to stop processing blocks.

Validators applied an interim fix to bring the network back online, but an edge case emerged the next morning. Around 5:00 a.m. PT on May 29, a different error code replaced the original cancellation reason and bypassed the guard the interim patch relied on. Validators halted the network again and deployed a more complete repair by about 8:30 a.m. PT.

A third outage occurred on May 29 from roughly 1:30 p.m. to 7:20 p.m. PT and had a separate cause related to end-of-epoch setup. When Sui moves to a new epoch, validators run a process to produce a shared random value used by some transactions. After the morning restart, too few validators participated in that setup and the process was disabled for the epoch. A latent bug prevented that disabled outcome from being written to disk. When validators restarted, they had no record of the failed setup and continued waiting for a result that would not arrive, stalling end-of-epoch logic and halting the network.

The Sui Core Team confirmed that no user funds were at risk and that the network did not revert any previously confirmed transactions during the outages. The team completed an incident review and listed priorities for development work, including strengthening end-of-epoch handling, refactoring gas-charging logic to make it more modular and testable, and adding failure containment so a single malformed input cannot stop the entire network.

SUI traded around $0.88 during the period, down about 2.6% over the prior 24 hours, with a market capitalization near $3.5 billion and a ranking around 32 by market cap. The incidents follow the network’s earlier $10 million security commitment after the Cetus exploit. The Sui Core Team and validators said they will continue work to harden the chain ahead of future upgrades.