Three Sui mainnet halts in 48 hours traced to an upgrade bug by developers
Sui blamed three mainnet halts on a v1.72 upgrade bug tied to gas charging and validator restarts. No funds were lost, but SUI fell about 19% on the week.
Intelligence analysis by GPT-5.4 Mini
Sui’s foundation said a new v1.72 feature exposed an edge case that caused three outages across May 28 and 29. The incidents were linked to gas-handling bugs and a follow-on randomness failure after validators restarted.
Sui is like a big shared notebook that many computers help keep in order. A new update added a feature, but it mixed badly with old rules for how to pay fees, so the notebook stopped working three times.
The team fixed one problem, but that fix had a small crack in it. Another problem showed up the next day, and then a third problem appeared when the computers restarted and forgot something important.
No one lost their money, but the network still had a rough week. It is like a train that keeps stopping even though the passengers are safe: people may not be hurt, but they lose trust in the ride.
Analysis
What happened
The Sui Foundation said three mainnet halts over May 28 and 29 were traced to interactions between a new address-balance feature in v1.72 and the network’s existing gas and consensus logic. The first outage lasted close to seven hours and came from a rare gas-charging edge case involving mixed payments made with the new feature and older coin objects.
According to the post-mortem, validators crashed with an underflow error when a transaction was canceled for insufficient funds, but the gas-smashing routine still tried to spend those same funds. The team restored the network with an interim fix around 1:30 p.m. PT, but it carried a known low-probability risk of another halt.
That risk showed up the next morning. A second outage began around 5 a.m. PT on Friday when a related transaction path bypassed the interim patch. The core team then deployed a more robust fix, which validators adopted by about 9:40 a.m. PT.
Why the third halt happened
The third outage was a knock-on effect from the second. When validators restarted to install the stronger fix, participation in the protocol that bootstraps on-chain randomness fell below the threshold needed to keep it active, so randomness disabled itself. The foundation said a latent bug then failed to persist that disabled state to disk. On the next restart, validators did not know randomness had been turned off, and the next epoch change stalled for close to six hours as randomness-dependent transactions backed up.
The foundation said no user funds were at risk and no committed transactions were reversed. Even so, CoinDesk data showed SUI fell roughly 8% during the cascade to about $0.90 and was down about 19% on the week. The incidents were Sui’s third major reliability failure since mainnet launch in 2023, following a transaction scheduling bug in November 2024 and a consensus divergence in January 2026.
Key points
- Sui said three mainnet halts were traced to a bug introduced by its v1.72 upgrade.
- The first two outages involved gas-charging errors tied to mixed payment handling and insufficient funds.
- The third outage followed validator restarts and a bug that failed to persist randomness being disabled.
- The foundation said no user funds were lost and no committed transactions were reversed.
- SUI fell about 19% on the week amid the outage cascade.
