An Opus 4.8 Audit Uncovered Zcash’s Bug — ZEC Plunged 30%

Privacy-focused cryptocurrency Zcash (ZEC) has emerged as one of the worst-performing digital assets in the market today.

The altcoin plunged more than 30% over the past 24 hours, falling to an intraday low of $385.8 during early Asian trading. 

Why is Zcash’s Price Falling?

The latest drop pushed ZEC to its lowest level since early May. While the broader crypto market downturn dragged many assets into the red, Zcash’s double-digit losses were exacerbated by a key development that intensified selling pressure.

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BeInCrypto reported earlier this week that the team shipped an emergency upgrade to patch a critical bug in the Orchard shielded pool, a move that initially lifted the price. That sentiment has since reversed.

In a post on X, Zcash founder Zooko Wilcox laid out the details. He said Taylor Hornby uncovered the counterfeiting vulnerability on May 29, 2026, by running a custom auditing agent framework paired with the newly released Opus 4.8 model.

Wilcox added that, even with the fix deployed, Shielded Labs felt it was important to share further context with users.

The flaw had gone unnoticed in Orchard since the pool launched in May 2022, and engineers only closed it on June 2. Shielded Labs said exploitation before the patch appears unlikely, though it cannot prove that cryptographically.

“What makes this particularly challenging is that, due to the privacy properties of Orchard and the nature of the bug, there is no definitive way to determine using only cryptography whether such exploitation occurred before the vulnerability was discovered and fixed. We believe it is important to be transparent about that uncertainty,” the post read.

btw this isn’t the first time a bug like this was discovered in zcash. last time it was disclosed after being a year+ in the wild and everyone lost faith and zcash went to zero for 7 years, until they found a new generation of buyers who doesn’t know the history (that’s you)

— Udi Wertheimer (@udiWertheimer) June 4, 2026

Shielded Labs is now looking into a network upgrade so anyone can verify the ZEC supply. The plan would add a new shielded pool and enforce turnstile accounting on all coins leaving Orchard.

Nonetheless, the episode exposed an uncomfortable tension at the center of Zcash. The same privacy that defines the network also makes its supply hard to audit.

“Privacy becoming a bug not a feature,” an analyst wrote.

The concern also reached prominent holders. Investor Arthur Hayes said he exited his entire position after the disclosure.

The Holy Trinity is dead. Sadly due to the Orchard Pool exploit, I had to dump our entire $ZEC bag.– While I think it's extremely unlikely of any minting, it cannot be formally cryptographically proved impossible– The privacy from AI, govt, big tech narrative demands perfection…

— Arthur Hayes (@CryptoHayes) June 5, 2026

Shielded Labs has promised a detailed upgrade proposal next week, though any supply-proof mechanism must still clear Zcash’s governance process. The coming days will test whether a cryptographic guarantee can win back the confidence the disclosure shook loose.

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