Zcash token plummets 50% after AI uncovers hidden flaw in four-year-old cryptography, raising concerns that machine intelligence is reshaping the advantage between code defenders and attackers.

What happened: A security researcher working with Zcash used Anthropic's Claude Opus 4.8 to discover a critical vulnerability that had gone undetected for more than four years. After Zcash disclosed the flaw on June 4, the token tumbled about 50%.

Why it matters: The flaw was capable of creating an unlimited supply of tokens—striking at the core of Zcash's value as a privacy-focused cryptocurrency whose security rests on advanced cryptography. That an AI tool found what years of expert human judgment missed signals that machine intelligence is lowering barriers for attackers across the crypto industry, potentially creating an arms race between those securing networks and those trying to hack them.

What to watch: The incident demonstrates that the same AI tools helping developers audit code are also accessible to those seeking to exploit it. Investors reassessed Zcash's security foundation after learning that a flaw capable of undermining the entire token supply had persisted undetected since before the AI vulnerability discovery.