ZEC surges 10% as Zcash turns a bug scare into a resilience…

Zcash's ZEC token jumped roughly 10% to near $620 — touching an intraday high above $642 — on the same session that Bitcoin and Ethereum each shed more than 4%, making it the standout winner in a broadly weak crypto market. The catalyst was a resolved security incident that briefly looked like a chain halt.

Why it matters

Block explorers appeared to show Zcash had stopped producing blocks for several hours, triggering a short-lived scare. The reality was more nuanced: developers had deliberately disabled Orchard — the network's newest shielded pool, introduced with NU5 in 2022 — via an emergency soft fork while they prepared a permanent fix for a soundness vulnerability in its zero-knowledge proof circuit. A soundness flaw can allow a system to accept invalid transactions; in this case, the Zcash Foundation confirmed successful exploitation could have enabled double-spending inside Orchard, though it could not inflate the hard-capped 21 million ZEC supply. The vulnerability was discovered May 29 by independent researcher Taylor Hornby. Private coordination with miners, exchanges, and infrastructure providers began May 31. A soft fork activated around 02:00 UTC on June 2, and the NU6.2 hard fork — which re-enabled Orchard using a corrected circuit — activated at block height 3,364,600 early June 3. The Foundation called it only the second security-driven protocol upgrade in Zcash's history since 2016.

Market impact

The price reaction inverted the usual script: a disclosed vulnerability, swiftly contained and patched before any known exploitation, read to traders as a proof of network resilience rather than a lasting impairment.