Critical vulnerability in the Zcash cryptocurrency discovered with Claude Opus

A critical flaw was discovered in Zcash’s Orchard privacy pool that could have allowed an attacker to create unlimited counterfeit ZEC while making the transactions appear valid and remain undetectable. The flaw was present from Orchard’s activation in May 2022 until an emergency fix was deployed on June 1, 2026. Cryptography alone cannot determine whether the flaw was exploited during that period.