Neo has released version 3.7.5, a hotfix update aimed at addressing an edge case vulnerability where method calls performed after a contract update would check permissions using the updated contract state instead of the original executing context.

Though checks against MainNet and TestNet state revealed no instances in the ledger history where the adjustment would modify past behavior, the decision was made to only enforce the change after a hard fork. This fork, Neo’s fourth, is named Domovoi and will be carried out at block heights 5,570,000 and 4,144,000 for MainNet and TestNet respectively.

The upgrade also fixes an issue where the System.Runtime.GetNotifications call can be used to exceed NeoVM’s MaxStackSize limit due to incorrect VM item reference counting.

Following recent updates to the core, resynchronization should not be required when upgrading, assuming the upgrade is performed from version 3.7.4 and prior to the fork heights being reached.