Poisoning Claude Code: One GitHub Issue to Break the Supply Chain (opens in new tab)

Introduction Hello, I’m RyotaK ( @ryotkak ), a security researcher at GMO Flatt Security Inc. After publishing my previous article ( Pwning Claude Code in 8 Different Ways ), I continued investigating Claude-related products and found several more vulnerabilities. In this article, I will explain a vulnerability in Claude Code’s GitHub Actions that could allow an attacker to compromise any repository that uses the Claude Code workflow, including Anthropic’s own repositories.1 Note: Variants of...