Overview
- Developers traced a flaw in Orchard’s zero‑knowledge proof circuit to code introduced in 2022 and disclosed the bug after a researcher found it on May 29, 2026; an emergency soft fork deactivated Orchard on June 2 and a hard fork (NU6.2) reinstated a corrected circuit on June 3.
- The fixes restored shielded transactions and developers report no detected exploitation or loss of funds while more than 4.5 million ZEC that had been in the Orchard pool were temporarily frozen during the repair.
- Three core developers coordinated directly with three dominant mining pools to deploy the emergency forks without prior public notice, a move that critics say highlights centralization and poor community governance.
- Orchard’s design hides transaction amounts so node operators cannot cryptographically prove that counterfeit coins were not created, a privacy trade‑off that leaves room for disagreement about whether any stealth exploitation could have occurred.
- Markets reacted sharply with ZEC prices sliding roughly 30–50 percent, some investors like Dragonfly say the immediate risk looks limited, and calls are growing for formal verification of circuits, new shielded‑pool accounting, and broader emergency‑response governance.