Core Transfers Halted on Exchanges as Core DAO Prepares Emergency Fork

Core DAO has begun coordinating an emergency hard fork after a small group of validators obtained CORE block rewards above the blockchain’s intended issuance, prompting several cryptocurrency exchanges to restrict token transfers. The network said the issue has been contained and user assets remain safe, while the permanent fix will be deployed as a forward upgrade rather than a rollback. Validator Reward Exploit Prompts Exchange Restrictions Core disclosed the problem on Monday, saying a small number of validators were accruing block rewards significantly above the amount intended under the protocol. The project said it had identified the root cause and was working on mitigation measures, describing the issue as limited to reward issuance only. In a status update, Core said: We're aware of an issue causing a small number of validators to accrue block rewards above the protocol's intended issuance.The root cause is identified and mitigations are in progress. User assets are safe. This affects reward issuance only, not... By Tuesday, the team said the activity had been contained and that it was coordinating an emergency hard fork with its validator set. In a follow-up post on X, Core wrote: "Update: the issue is contained and the malicious validators can no longer draw excess rewards." The network added that it was "coordinating an emergency hardfork with validators to deploy the permanent fix." Several exchanges moved to restrict CORE token transfers while the situation unfolded. Core did not name the exchanges involved, and the project has not disclosed whether the restriction affected deposits, withdrawals, or both. What the Emergency Hard Fork Changes Core said the planned upgrade is a forward upgrade, not a rollback. That distinction means the fork will change network rules from a specified point onward without rewriting transactions already confirmed on the blockchain. Previously recorded blocks and transactions are expected to remain unchanged. The network said it is working with validators on a permanent fix through this forward upgrade. It also stated: "Assets remain safe. Full post-mortem to follow." Incident Phase Core DAO Response Exchange and User Impact Initial discovery Root cause identified; mitigations in progress User assets reported safe; reward issuance only affected Containment Malicious validators blocked from drawing excess rewards Several exchanges restricted CORE token transfers Permanent fix Emergency hard fork coordinated with validators Confirmed transactions remain unchanged; post-mortem pending Unanswered Questions Around Excess Rewards Core has not published several key details about the incident, leaving the full scale of the event unclear. The project has not disclosed: The total amount of CORE distributed through the exploit The number of validators involved How long the validators were able to claim excess rewards Whether any of the additional tokens reached the open market The technical vulnerability that allowed the excess rewards to be drawn Core also has not announced an activation time for the emergency hard fork. The lack of detail makes it difficult to assess how much excess issuance occurred before the network contained the activity. Security and Custody Questions Core has repeatedly emphasized that the issue did not affect network security or the custody of user assets. The project said the vulnerability was specific to reward issuance, not to the broader blockchain protocol. Still, the incident highlights the risk that validator behavior can create unintended token issuance in proof-of-stake networks. Because the fork is designed as a forward upgrade, the response avoids the complexity and controversy of a rollback, but it leaves the underlying vulnerability details undisclosed for now. Core said a full technical postmortem would be published after the response is completed. Until then, exchanges, validators and CORE holders are waiting for more clarity on the scope of the excess rewards and the precise timing of the fork. Why Did Core Halt Transfers on Exchanges? Several exchanges restricted CORE token transfers after Core DAO said a small group of validators accrued block rewards above the protocol’s intended issuance. The network said the issue was contained and user assets were safe. What Is the Core Emergency Hard Fork? It is a forward upgrade to change network rules and stop validators from drawing excess rewards. It is not a rollback, so previously confirmed transactions remain unchanged. Are User Assets Safe on Core? Core has said user assets are safe and that the incident affects reward issuance only, not network security or custody. A full post-mortem is expected after the response is completed. What Are “Malicious Validators” in the Core Incident? Core described them as a small group of validators that used a vulnerability to claim CORE block rewards above intended issuance. Core said they can no longer draw excess rewards. Will the Core Fork Change Existing Transactions? No, the planned emergency hard fork is a forward upgrade, not a rollback, so confirmed transactions on the blockchain will remain unchanged.