Ontology stopped producing blocks on its mainnet Aug. 31 after its core development team flagged a potential security concern during a routine daily check. The chain's block explorer showed production frozen at block 20,770,893. With block production offline, no transactions submitted to the Ontology mainnet can be processed until the network resumes.
The team issued an official announcement describing the halt as a preventive measure, not a response to a confirmed exploit or active attack. Validators and developers are conducting an emergency review of the mainnet and related components to determine whether the flagged concern represents an actual vulnerability.
Ontology has not disclosed which component triggered the review, the technical nature of the potential issue, or whether developers have identified a specific flaw requiring a software patch. The network has also not provided an estimated timeline for restarting block production.
"Block production will remain temporarily suspended," Ontology said in its official announcement, adding that the network will not restart until it has been "sufficiently assessed and deemed safe to operate."
Ontology confirmed no evidence of unauthorized asset movement or theft. "There is currently no indication of any loss or compromise of user assets," the team said. "ONT, ONG, and other on-chain assets remain unaffected based on our current assessment."
The team told users not to attempt time-sensitive on-chain transactions involving ONT, ONG or other assets while the pause remains in place.
Ontology said it is working with validators and ecosystem partners throughout the investigation. The team committed to releasing a separate announcement before or at the moment block production resumes, covering the results of the security assessment and any required upgrades. South Korean exchanges Bithumb and Upbit suspended deposits and withdrawals for ONT and ONG following the halt.
