In today’s crypto update, Zcash (ZEC) plunged as much as 46% after founder Zooko Wilcox disclosed a critical vulnerability that could have allowed attackers to create unlimited counterfeit tokens. The announcement sparked a sharp selloff as investors reassessed their exposure to the privacy-focused cryptocurrency and questioned the integrity of the network’s supply.
Critical Counterfeiting Bug Triggers Emergency Response
Wilcox revealed that security researcher Taylor Hornby discovered a critical vulnerability in Zcash’s Orchard shielded pool on May 29. The flaw could have allowed the creation of counterfeit ZEC without detection. For context, Shielded Labs hired Hornby in April 2026 to conduct ongoing security research on the Zcash protocol. Using AI-assisted auditing tools alongside traditional security methods, he eventually uncovered the vulnerability.
Interestingly, the discovery triggered an emergency response coordinated by the Zcash Open Development Lab. Developers and security teams moved quickly to contain the risk, completing remediation efforts on June 2.
Shielded Labs later confirmed the vulnerability was real and exploitable. Internal testing reportedly showed that unlimited counterfeit ZEC could be generated while remaining undetectable.
However, the organization acknowledged that Orchard’s privacy features make it impossible to cryptographically prove whether the flaw was exploited before it was fixed. Shielded Labs also hinted at a future network upgrade to strengthen user protections and validate the integrity of Zcash’s supply.
Investors Pull Back as Confidence Wavers
Meanwhile, investors reduced their exposure following the disclosure. Concerns about undetected counterfeit ZECs weighed heavily on market sentiment and triggered widespread selling. Among the notable sellers was Arthur Hayes, who confirmed that he had sold his entire ZEC position. Hayes described the move as the end of his so-called “Holy Trinity” portfolio, following his previous exits from HYPE and NEAR.
According to Hayes, privacy-focused cryptocurrencies require near-perfect security guarantees. While he believes exploitation was unlikely, he argued that it cannot be proven impossible by cryptography. He added that the privacy narrative demands certainty rather than probability.
Further, he also said he initially underestimated the significance of the exploit. However, after witnessing ZEC’s sharp decline, he reassessed his thesis and exited the position. Despite the sale, Hayes said he could re-enter if future developments restore confidence in the network.
ZEC Suffers One of Its Sharpest Declines
The market reaction was swift. ZEC quickly dropped nearly 30% to the $440 region as news of the vulnerability spread across the market.
Selling pressure intensified in the following hours, pushing the token down more than 46% to a 24-hour low of around $255. The decline ranked among the sharpest single-day drops for the cryptocurrency in recent years.
However, the cryptocurrency has since recovered some losses. According to CoinMarketCap data, ZEC is currently trading around $319. Despite the rebound, the token remains down more than 43% over the past 24 hours as investors continue to assess the implications of the vulnerability disclosure.
Josiah Oluwadare
