A security researcher found a flaw in Anthropic's Claude Code GitHub Action that let an attacker take over vulnerable public repositories running it, with nothing more than a single opened GitHub issue. Because Anthropic's own action repo used the same workflow, a working attack could have pushed malicious code into the action itself and onto the projects downstream that pull it.

RyotaK of GMO



Source: TheHackerNews
Source Link: https://thehackernews.com/2026/06/claude-code-github-action-flaw-let-one.html