Foreign media reported that Zcash recently patched a critical vulnerability in its Orchard privacy pool, but market selling pressure did not ease. The reason is not whether the vulnerability has been fixed, but rather that the network cannot prove this flaw was never exploited in the past four years, casting doubt on the credibility of its supply.
This opinion piece argues that the incident reveals not a single software flaw, but a long-standing challenge inherent to privacy coins: the more difficult a transaction is for outsiders to audit, the harder it becomes to independently verify the integrity of the supply. For networks that rely on privacy, this very uncertainty can directly impact price.
The vulnerability could allow for the forgery of ZEC.
The issue occurred in Orchard, the core privacy pool in Zcash's shielded transaction system, used to conceal addresses and transaction amounts. According to disclosure by Shielded Labs, this circuit vulnerability could theoretically allow attackers to generate additional ZEC undetected, with no upper limit on the amount.
Security researcher Taylor Hornby discovered the issue on May 29, 2026. The report states that he used AI-assisted tools during a targeted audit of the Orchard circuit and verified feasibility in a local test environment. The development team subsequently moved quickly to implement a fix.
- Vulnerability discovery date: May 29, 2026
- Emergency hard fork completion time: June 1, 2026
- Affected Module: Orchard Privacy Pool Circuit
Even after the repair, the market still plummeted.
Within days of disclosure, the developers disabled the vulnerable component and redeployed the patched circuit via an emergency hard fork. In line with standard security incident response practices, the response was timely, with no evidence of stolen funds or clear signs of inflation detected.
However, the commentary points out that the market is truly concerned about “what has happened in the past,” rather than “whether it has been fixed for the future.” Since Orchard has been live since May 2022, this means the vulnerability remained undetected in the network for approximately four years. While Zcash can confirm that the patch is effective, it cannot cryptographically prove that no one exploited this flaw during those four years.
The report noted that ZEC rose above $600 in the week the vulnerability was discovered, then dropped approximately 45% to around $314 after disclosure, erasing over $3 billion in market capitalization. The article also stated that Arthur Hayes, co-founder of BitMEX, sold his entire ZEC position following the public disclosure, further amplifying market sensitivity to supply concerns.
The conflict between privacy and auditability is further amplified.
The article argues that this incident has caused sustained disruption because Zcash’s privacy design inherently limits external audit capabilities. With transparent blockchains like Bitcoin, outsiders can directly verify the public ledger to confirm whether the total supply is abnormal; however, in shielded transaction pools, addresses and amounts are concealed, making it difficult for external parties to reach the same direct conclusions.
This is also the long-standing trade-off faced by privacy coins: stronger privacy protection often means weaker independent auditability. The article states that this is not an issue that can be fully resolved by a single patch, but rather a reality that privacy-focused networks must confront by design.
Shielded Labs is currently advancing formal verification of the Orchard circuit and proposing subsequent network upgrades, including the introduction of a new shielded pool and the use of a "turnstile" accounting method to track funds flowing out of the existing Orchard pool, aiming to enhance supply verifiability while preserving privacy features.
If this solution is implemented, it could serve as a reference model for addressing audit concerns related to privacy coins. However, before that, the market still needs to absorb a more immediate reality: a vulnerability being patched does not mean historical risks have been fully eliminated.