Chainguard launches Harness: AI bug-hunting with Claude Mythos 5.1

Chainguard has launched Harness, an AI-powered security tool that uses frontier models, including the restricted Claude Mythos 5.1, to find and fix exploitable vulnerabilities in application code. A Wakefield Research survey found 66% of companies with $1B+ revenue knowingly leave critical bugs unpatched at least sometimes.

• Harness uses Claude Mythos 5.1, access to which is limited to Project Glasswing participants
• 66% of companies with $1B+ revenue leave critical vulnerabilities unpatched at least sometimes
• Among companies under $250M in revenue, that figure drops to 27%
• Harness will be available via Anthropic's Claude Marketplace using existing spend commitments