What happened to the Zcash (ZEC) network?

Zcash developers discovered a critical vulnerability in the Orchard shielded pool and deployed an emergency network upgrade to fix it. Orchard transactions were temporarily disabled before being safely restored.

Was the Zcash vulnerability exploited?

According to the Zcash Foundation, there is no evidence that the vulnerability was exploited. The Foundation also said there was no unauthorised creation of funds and no impact on user privacy.

What was the Orchard vulnerability in Zcash?

The flaw affected Orchard’s zero-knowledge proof circuit, a core component of Zcash’s privacy technology. The bug could have allowed invalid state transitions within the shielded pool if left unpatched.

Did Zcash users lose funds because of the bug?

No. The Zcash Foundation stated that no unauthorised value creation was detected and user funds were not reported as being at risk. The issue was addressed before any known exploitation occurred.

Why did Zcash temporarily disable Orchard transactions?

Developers used a two-step emergency response to minimise risk. Orchard actions were first disabled through Zebra 4.5.3 and later restored through the NU6.2 network upgrade with a corrected circuit.

Was the Zcash network actually down?

Not completely. Some community members reported outages because certain block explorers stopped updating, but blocks continued to be mined and the network remained operational during the upgrade process.

Who discovered the Zcash vulnerability?

Independent security researcher Taylor Hornby identified the issue on May 29 during an ongoing protocol audit for Shielded Labs. Zcash engineers subsequently verified the flaw and prepared a fix.

Why is this incident important for Zcash investors?

The event highlights the importance of ongoing security audits and rapid incident response in privacy-focused blockchains. While the vulnerability was serious, the successful fix without reported losses may reinforce confidence in Zcash's development process.

Image for illustrative purposes only. Not a real photo.

Zcash restores Orchard after emergency fix

Written by Liezl GambePublished Jun 4, 2026, 12:19 AM

Zcash developers restored Orchard transactions after deploying an emergency network upgrade to address a critical vulnerability discovered in the privacy-focused blockchain’s latest shielded pool.

The Zcash Foundation said the flaw affected Orchard’s zero-knowledge proof circuit and could have enabled invalid state transitions within the pool, although no evidence of exploitation or unauthorised value creation was found.

“The network experienced a brief period of instability as miners upgraded and converged on new consensus rules,”

Said Zcash Open Development Lab-affiliated contributor, Tatyana.

The issue was resolved through a two-step emergency process that first disabled Orchard transactions through Zebra 4.5.3 before reactivating the shielded pool with a corrected circuit under the NU6.2 upgrade in Zebra 5.0.0.

The vulnerability was discovered on May 29 by independent security researcher Taylor Hornby during an ongoing protocol audit for Shielded Labs, after which Zcash engineers confirmed the issue and developed remediation measures.

The upgrade triggered confusion across parts of the ecosystem after some block explorers appeared to stop updating, prompting reports on social media that the network had gone offline despite blocks continuing to be mined.

Following the incident, Zcash’s ZEC token briefly fell to $599 from a daily high of $637 before recovering to around $614 as network stability returned and concerns over the vulnerability eased.

At the time of reporting, Zcash price was $627.25.