Zcash fixes Orchard bug, re-enables shielded transactions, price rebounds after 50% crash

2 min

Zcash fixes a critical Orchard bug via a two-phase emergency upgrade. ZEC crashed ~50%, then started to recover after confirmation the network is secure.

Zcash completes emergency patch; price stabilizes

Electric Coin Company CEO Josh Swihart said the fix is complete and the network is secure on June 7. He posted this on X.

ZEC fell from $624 on June 4 to $309 on June 5. The slide erased over $3B in market cap, per the documented timeline. After the fix, the price began to rebound.

ZECUSD chart

What went wrong

- The bug was found on May 29, 2026 by security researcher Taylor Hornby during a Shielded Labs audit.
- It was a “soundness” flaw in the Orchard Action circuit. An under‑constrained element allowed invalid state transitions.
- A local proof-of-concept generated unlimited, undetectable counterfeit ZEC in tests using Claude Opus 4.8 and a custom toolset.
- Zcash’s turnstile accounting showed no unauthorized value creation on mainnet.
- Due to Orchard’s privacy, exploitation cannot be definitively ruled in or out.
- The flaw existed since Orchard’s May 2022 activation.

How they fixed it

- Phase 1: Emergency soft fork via Zebra 4.5.3 at block 3,363,426 on June 2. Orchard transactions were disabled. Transparent and Sapling kept running.
- Phase 2: NU6.2 hard fork via Zebra 5.0.0 at block 3,364,600 on June 3. The corrected circuit and a new verifying key re‑enabled Orchard.

Market reaction

- ZEC rose from $544 on June 2 to $603 on June 3, then to $624 on June 4.
- Arthur Hayes said he exited ZEC on June 4. The coin dropped to $309 on June 5 amid lingering uncertainty.
- Swihart’s June 7 update helped restore confidence. ZEC trades around $430 at press time.