As part of routine auditing and security review processes, an issue affecting the Zcash Orchard pool was identified over the weekend. Orchard-related transactions are not being mined. Privacy is unaffected. All funds are safe.
To protect Zcash users and the integrity of the network, developers, infrastructure operators, and other independent participants across the Zcash ecosystem have come together to coordinate a protocol update that requires a temporary suspension of Orchard pool activity during the upgrade rollout.
Orchard transactions are expected to be re-enabled at 14:00 EDT on June 2, 2026. We will provide a status update at 10:00 EDT.
Key Facts:
The issue does not affect the privacy of any funds.
The issue was identified through routine auditing before any known exploitation.
The issue affects only Orchard, Zcash’s latest shielded pool.
Only Orchard pool transactions will be suspended during the upgrade window. Wallet users will be unable to send or receive Orchard funds until the upgrade is complete.
With the exception of the shielded Orchard pool, the Zcash network continues running. Transactions to and from the shielded Sapling and transparent pools are unaffected.
ZEC held on exchanges is unaffected and can continue to be traded normally.
This issue required a protocol-level change, which took effect at 22:30 EDT on June 1, 2026
This effort relies on voluntary cooperation among independent participants throughout the network. As part of our responsible disclosure, we are also notifying the maintainers of other protocols that have deployed Orchard.
Additional information will be shared when the upgrade is complete.
We can’t say much at this very moment. Zcash core developers make responsible use of AI to enhance protocol development, strengthen our specifications, formalize our code and many other things that make us stronger.
I upgraded Cipherscan Zebra to v4.5.3 within 30 minutes of the notification and have been monitoring since.
During the soft-fork transition I saw multiple competing forks as miners upgraded. The longest was a 25-block fork (heights 3363431-3363455), plus scattered orphans as stragglers came online. 37 orphaned blocks total.
I cleaned up the database (had 45 stale block hashes from the competing chains), re-indexed from scratch, and everything is back in sync.
Also shipped a fork watch page so people can see what happened: cipherscan.app/reorgs, shows orphaned blocks, fork events, which miners were on the old chain, etc. There’s a public API endpoint too if anyone running nodes wants to report competing tips.
All services running: explorer, API, lightwalletd. Happy to help with anything else.
I’ll keep an eye on the report once the problem is resolved. It’s important to clarify that Orchard transactions have been suspended; I don’t think that was communicated well. I read some comments that it’s because the miners aren’t accepting Orchard transactions, which sounds different. All the best, and I hope everything gets resolved soon.
At my job, I manage several web services, and much of the software I rely on has required urgent security upgrades in recent weeks and months. The Linux Copy Fail and that NGINX buffer overflow are just a couple of examples that made headlines. I have no insider info on this specific issue, but it wouldn’t surprise me if it were another vulnerability discovered via agentic AI. This is a difficult phase for our industry; patching frequently and rapidly is the only solution until even better AI code review and formal verification arrive.
Thank you to everyone working to keep the network safe. Given the current state of the industry, these proactive measures are exactly what we want to see. Honestly, if I were hosting a complex distributed system on the public internet that hadn’t had a security update in months, I would be much more worried.
In an abundance of caution we intentionally disabled Zec.rocks globally for 26 minutes during the network reorganization to protect users until the network settled.
Well, I’ve noticed that the price of ZEC has remained stable today compared to everything else. Apparently, this is because exchange deposits are closed. I wouldn’t rule out the possibility that market conditions will develop in such a way that people will later be glad they couldn’t sell their coins due to technical restrictions. For example, I remember a similar restriction in December 2017 for Bitcoin, when the entire blockchain was paralyzed, and people couldn’t sell their BTC while it steadily rose to 17,000.
Update: Coordinated Network Upgrade for Orchard transactions.
The network upgrade is in progress. During this period, the Zcash network continues to run, and transparent and Sapling-shielded transactions are functioning normally. The Network Upgrade is specific to the mining of Orchard transactions.
There is no evidence of any exploit. Your funds and privacy are safe. No user action is needed.
Ecosystem-wide coordination includes deployment of both consensus nodes: zcashd, zebrad, as well as SDKs and other supporting infrastructure. As part of this coordinated rollout, several mining pools requested additional time to complete deployment and quality-control procedures, particularly given the need to coordinate teams and operators across multiple time zones.
We anticipate that miners will begin accepting Orchard transactions again at approximately 23:00 EDT.
Additional information will be shared when the upgrade is complete.
