TL;DR:
- The technical glitch affected Orchard’s zero-knowledge proof circuit, potentially allowing invalid state transitions within the shielded pool.
- Developers deployed the Zebra 4.5.3 and Zebra 5.0.0 (NU6.2) updates to temporarily disable and then reactivate the patched protocol.
- Following the incident, the native token ZEC recorded a price fluctuation over the last 24 hours, moving in a range between $637 and $599.
Zcash developers temporarily suspended transactions in their Orchard shielded pool after discovering a critical vulnerability in the network’s privacy infrastructure. The Zcash Foundation reported that the bug was originally detected on May 29, 2026, during an independent protocol audit conducted for Shielded Labs.
They reported that the error was located in the zero-knowledge proof circuit. According to the technical report, the security flaw could have allowed invalid state transitions in Orchard.
However, engineers found no signs of the flaw being exploited on the blockchain. The Zcash Foundation confirmed that no unauthorized value creation was detected, nor were there any breaches of user privacy.
The resolution of the technical issue required the coordinated deployment of a two-phase consecutive emergency update. Nodes running Zebra 4.5.3 first disabled Orchard features, while version Zebra 5.0.0 activated the NU6.2 fork to restore service.
Community confusion over node stability
The application of the security patch generated contradictory reports among users and network block explorers. One explorer showed discrepancies of up to four hours in the logging of block 3,364,601, sparking alerts on social media about an alleged total system outage.
Tatyana, a contributor to the Zcash Open Development Lab (ZODL), explained that the platform experienced a brief period of instability while miners converged on the new consensus rules. Data shared by the specialist indicates that network stability was restored around 3:00 am on June 2, 2026.
Tech sector executives downplayed the scope of the incident on the blockchain infrastructure. Mert Mumtaz, CEO of the firm Helius, stated on public platforms that the network remained operational and attributed the alerts to several explorers being connected to outdated nodes.
On the other hand, community user Railgoon detailed that miners intentionally froze the privacy pool. In his view, this measure represented a controlled partial halt to fix the code before the hard fork.
The crypto market reacted with volatility to the news of the emergency network update. Data from the CoinGecko platform shows that the price of ZEC dropped to a daily low of $599 after trading at $637, later stabilizing around $614.
The privacy ecosystem is now focused on monitoring the remaining nodes. The Zcash Foundation expects the total of exchange operators and miners to adopt version NU6.2 in the coming days to consolidate the new consensus.