Sui’s mainnet stopped processing user transactions three separate times between May 28 and May 29, 2026. All three halts traced to a single root cause: a gas-charging logic bug introduced in the v1.72 protocol upgrade. The first fix triggered a second outage. The second fix exposed a third, unrelated bug during validator restarts. SUI fell approximately 19% over the week. $1.88 million in leveraged positions were liquidated. And the Sui Foundation was forced to publish a post-mortem acknowledging it knowingly deployed a patch with a residual risk that later materialized.
No user funds were lost. No committed transactions were reversed when the network resumed. But the sequence represents Sui’s third major reliability incident since its 2023 mainnet launch, drawing immediate comparisons to Solana’s early-era stability struggles, and raises a pointed question about whether a Layer 1 blockchain billing itself as fast enough for financial institutions should be halting at all.
What v1.72 Changed and Where the Bug Lived
The v1.72 upgrade introduced two features simultaneously: an address balances accounting model that allows users to pay transaction fees directly from their address balance rather than from discrete coin objects, and gasless stablecoin transfer pathways designed to reduce friction for everyday users. The combination of these two features created an edge case that the upgrade’s testing did not catch.
The bug manifested through a process called gas smashing, where the network combines multiple input coins into a single coin to pay transaction fees. When a transaction was canceled because the account lacked sufficient funds, the gas smashing step had already attempted to spend those same funds. This created a negative balance delta, an account showing that it owed more than it held, that crashed the validator settlement process. The first halt began at approximately 7:00 AM PDT on May 28 and lasted roughly six hours before validators deployed a patch and the network resumed.
The Fix That Made It Worse
The Sui Foundation’s post-mortem contains an admission that is unusual in blockchain incident reviews. The interim patch deployed to resolve the first outage contained a known residual risk, a low-probability failure condition that developers acknowledged before deploying. The decision to ship the patch anyway rather than wait for a complete fix was a judgment call: get the network running with an imperfect fix, or leave it down while building a cleaner solution. They chose speed. The residual risk materialized.
When validators upgraded to the patched version on May 29, a variation of the same gas-charging bug that had been partially addressed resurfaced through a different code path, bypassing the temporary safeguard and triggering the second halt. This lasted approximately 3.5 hours. The third outage was mechanically separate: during the validator restarts required to install the fix for the second halt, a latent bug in Sui’s distributed key generation process, which initializes the network’s randomness beacon at each epoch transition, prevented the network from completing its validator restart sequence. User transactions stopped being accepted for approximately six more hours before the final fix was deployed.
1. When each halt happened and how long it lasted
When Each Halt Happened and How Long It Lasted
May 28–29, 2026 | All three caused by v1.72 upgrade
Gas smashing negative balance (6h)
Same bug, different code path (3.5h)
DKG randomness bug during restart (5.8h)
Source: Sui Foundation post-mortem May 31, 2026 | @cryptonewsbytes
2. SUI price during and after the outages
SUI Price: Before, During, and After the Outages
May 26 – June 1, 2026
Bar length = relative price. Red bars = outage days. SUI peaked at $1.41 earlier in May before falling.
Source: CoinGecko | @cryptonewsbytes
3. SUI vs broader crypto market: weekly performance
SUI vs Crypto Market: Weekly Performance (May 26 – Jun 1)
SUI -19% vs broader market -4% to -11%
SUI underperformed every major crypto by 10+ percentage points. Bar length = severity of weekly decline.
Source: CoinGecko | @cryptonewsbytes
Further Reading
The broader institutional sentiment context for the week that Sui halted three times.
What NEAR was building at the same conference where Sui announced its zero-fee stablecoin ambitions.
The institutional clearing infrastructure being built around stablecoins. Context for why Sui’s reliability record matters to its ambitions.
This article is for informational purposes only and does not constitute financial advice. Sources: Sui Foundation post-mortem May 31, 2026; CoinDesk; CoinPaprika; CryptoTimes; FXStreet; 99Bitcoins. Published June 2, 2026.
