Zcash Schedules Ironwood Hard Fork to Seal Vulnerable Orchard Pool

Scheduled for block 3,428,143, the Ironwood upgrade—also designated as NU6.3—introduces a new shielded pool built on corrected cryptographic circuits. While security researcher Taylor Hornby discovered the Orchard vulnerability on May 29, the privacy-centric design of Zcash makes it impossible to definitively prove whether the bug was exploited to create counterfeit ZEC. By sealing the old pool, the network ensures that any funds exiting must pass through a turnstile mechanism, which enforces monetary rules and prevents the release of value exceeding legitimate historical deposits.

Although developers found no evidence of unauthorized value creation following the initial patch in the NU6.2 update, the hard fork serves as a definitive safeguard against hypothetical counterfeiting. Users are not required to take immediate action, though wallets and exchanges may temporarily pause deposits and withdrawals to facilitate the transition. Providers who have not yet migrated from the legacy zcashd client may experience extended service interruptions. Moving forward, the Zcash ecosystem is prioritizing formal verification and AI-assisted audits, such as those performed via Anthropic’s Mythos system, to bolster supply integrity and prevent future cryptographic risks.