How One Guy Used Claude Code to Discover a Billion-Dollar Bug

Taylor Hornby, a security researcher who works with Shielded Labs, discovered a bug on May 29, 2026 – just one day after Anthropic released Opus 4.8- that resulted in billions of dollars removed from the project’s market capitalization.

The flaw affected a shielded pool within the protocol’s design that powered private Zcash transactions, and was serious enough to trigger an emergency response across the entire ecosystem. It resulted in a sudden sell-off that saw ZEC’s price crash by roughly 60%, thereby erasing more than $4 billion in market cap.