Zcash Activates Emergency Forks After Orchard Flaw Raises Counterfeit ZEC Fears

Highlights:

• Zcash fixed a critical Orchard vulnerability through a soft fork and the NU6.2 hard fork.
• Mining pools and exchanges reviewed the emergency fixes before supporting the network upgrades.
• ZEC recovered more than 41% from its low as investor confidence improved after the security fix.

Josh Swihart, founder of Zcash Open Development Lab, explained today how developers fixed a critical vulnerability in Zcash’s Orchard shielded pool. In a post on X, Swihart said developers deployed a soft fork and the NU6.2 hard fork after discovering a flaw that could have enabled unlimited counterfeit ZEC creation.

Zcash Rebounds as Team Reveals Fix Details

Zcash (@Zcash) climbed 10% over the past 24 hours, extending its rebound after a sharp selloff that cut its value by more than half.

Zcash Open Development Lab founder Josh Swihart said the team deployed a two step emergency upgrade to… pic.twitter.com/A79UfUBDd5

— BSCN (@BSCNews) June 8, 2026

The vulnerability affected Orchard, Zcash’s main shielded pool that processes private transactions through zero-knowledge proofs. Orchard uses zero-knowledge proofs to validate transactions while hiding transaction details from public view. Shielded Labs said a late May audit uncovered a flaw that had existed inside the Orchard circuit.

Shielded Labs said the vulnerability could have allowed attackers to create unlimited counterfeit ZEC that validators could not detect. The flaw threatened Zcash’s supply integrity because counterfeit coins could have entered circulation without detection. After discovering the flaw during a late May audit, developers implemented emergency network changes before publicly disclosing the vulnerability.

Developers activated a soft fork on June 2 that disabled all Orchard transactions across the Zcash network. Swihart said developers withheld technical details during the initial response phase. The team wanted to reduce the risk of exploitation before completing a permanent fix. The June 2 soft fork disabled Orchard transactions so developers could prevent potential exploitation while preparing the NU6.2 fix.

Developers activated the NU6.2 hard fork on June 3, one day after disabling Orchard transactions. The NU6.2 hard fork fixed the vulnerability and restored Orchard transactions across the network. Users resumed private transactions after the upgrade went live.

Shielded Labs disclosed the vulnerability after developers completed the emergency upgrades and fixed the flaw. The organization said available evidence suggested attackers likely never exploited the vulnerability. However, Shielded Labs also said no cryptographic proof exists that can confirm nobody exploited the flaw before its discovery.

Mining Pools and Zcash Community Coordinate Recovery Effort

Mining pools, exchanges, developers, and infrastructure providers participated in the response after the vulnerability was made public. Swihart said ZODL coordinated with mining pools, exchanges, and infrastructure providers while preparing and deploying the upgrades.

Several mining pools and exchanges requested code reviews before agreeing to support the network upgrades. Developers shared code with trusted participants so mining pools and exchanges could verify the emergency fixes before deployment.

ViaBTC and Foundry helped coordinate network support and reviewed the proposed fixes before activation. Both mining pools helped communicate technical details to participants before the upgrades went live. Their involvement helped exchanges, infrastructure providers, and miners prepare for the network changes.

Swihart said the vulnerability allowed the network to test its emergency response procedures. Swihart said the response improved coordination between developers, exchanges, mining pools, and infrastructure operators.

Market Turbulence Shifts Attention Toward Ironwood

ZEC fell sharply after Shielded Labs disclosed the Zcash Orchard vulnerability and its potential counterfeit coin risk. The token dropped from roughly $630 to around $303. As of press time, the coin has recovered 8.33% to $427.66 in the past day. However, the trading volume is down 12.26% to $1.19 billion. The market cap stands at $7.13 billion.

The disclosure also drew reactions from prominent figures outside the immediate Zcash ecosystem. BitMEX co-founder Arthur Hayes said he sold his entire ZEC position after the vulnerability became public. Hayes joined a growing group of traders who reassessed their exposure following 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