The Sui Foundation on Sunday released a post-mortem analysis of three mainnet outages that brought down Layer 1 on May 28th and 29th, showing that the first two outages were caused by the gas charge bug introduced by the v1.72 “address balance” upgrade. The third issue was determined to be due to another random condition failure that became apparent when validators resumed installing the interim fix, and the team acknowledged that it shipped knowing there was a low risk of an outage.
According to CoinGecko, the network’s native token, SUI, fell 6.6% in the 24 hours after the fact and 18.5% in seven days to $0.82, reducing Sui’s market capitalization to $3.31 billion. The chain holds a total of $479.66 million locked, making it the 13th largest network tracked by DefiLlama, behind Avalanche and ahead of Monad. In Sunday’s 24-hour trading volume, the Sui-based DEX cleared $77.33 million. DeepBook V3 led the way with $26.69 million.
Last week, Sui restarted after consecutive outages related to the same 1.72 release. This is also one of the more detailed Layer 1 incident reports published this year, naming specific code paths and acknowledging that the validation network was temporarily executed on a fix that Mysten Labs engineers knew could fail.
bug that breaks the gas
The first two stops are tracked at the corners of the run. Sui calls it “gas smashing.” This is the process by which the runtime combines all input coins of a transaction into one coin and debits it as gas before the transaction itself is executed. The v1.72 release introduced “Address Balance”. This is a feature that allows users to withdraw from and deposit to a single address by issuing a balance delta where the system settlement transaction adjusts each block.
According to the Foundation, an edge case occurred when a transaction attempted to overdraft an address balance to cover gas, was correctly marked as canceled with an “InsufficientFundsForWithdraw” error, but then gas smashing was performed again on the same reservation object, consuming funds that the transaction was said to be unable to access. The payment layer received a negative delta applied to a zero balance and the validator crashed. If there is a crash bug in the input pipeline, all honest validators will hit the same bad input and the chain will stop.
Patches for known risks
Sui’s interim fix introduced Thursday to get the chain back on track was to stop performing gas smashes on transactions canceled with “InsufficientFundsForWithdraw.” The foundation now says the team has “accepted the risks associated with this proposal in order to get the outage network back on as quickly as possible, pending the development of a robust fix.” On Friday morning, the network encountered a variant of the same edge case and went out again. A second patch followed.
The third outage arrived several hours later at the next scheduled epoch change. Validators that resumed adopting Friday’s patch failed to meet the participation threshold for new epoch distributed key generation (the step in the protocol that initializes epoch randomness). Although DKG is automatically disabled by design, a potential bug prevented failure verdicts from being written to disk. As further restarts continued, each validator returned unaware that the DKG had failed, the queue of transactions relying on randomness grew, and the epoch termination logic stalled waiting for the DKG to never run. A permanent fix maintains DKG status across reboots and added a kill mechanism to converge validators on stuck epochs.
what is the problem
According to the foundation, no user funds were at risk and no committed transactions were rolled back throughout the three outages. These incidents were unrelated to traffic load or external exploits, and transactions returned to sub-second finality after the third restart. The foundation also said that an internal AI agent with access to production validator logs “significantly accelerated diagnostics.”
reliability bar
Context: Solana’s last officially confirmed mainnet outage was on February 6, 2024, when a bug in the validator program cache forced a coordinated restart of approximately 5 hours. In contrast, Sui experienced a brief outage in November 2024 due to a congestion control assertion, and prior to this run, it suffered a six-hour consensus outage in January 2026.
The Foundation has identified four restoration priorities: The idea is to extend Sui’s “safe mode” graceful degradation pattern throughout the remaining reconfiguration passes. Rebuild your gas charge logic to a code quality bar comparable to Move VM or Mysticeti consensus protocols. Expanding production debug AI agent programs. And it adds a layer of defense in depth that allows validators to skip inputs that cause crashes rather than stopping the chain.
Mysten Labs CEO Evan Cheng and Chief Product Officer Adeniyi Abiodun have not posted any public comments regarding the post-mortem at the time of publication. The Defiant has contacted the Sui Foundation for comment.
