A recently disclosed vulnerability in Anthropic’s Claude Code could enable an attacker to execute their commands on a developer's workstation by opening the AI coding assistant within a previously trusted repository This article explores agentic tools untrusted. . Security researcher Kevin Breen reported that Claude Code automatically processes a repository-root .mcp.json file when a session begins, which could potentially execute commands defined in the configuration before the user is prompted for approval.
However, once a developer trusts a repository, their trust reportedly extends to configuration and content checked out later, including branches associated with external pull requests. An attacker might disguise such an entry as a common developer tool, like a browser testing tool, database, telemetry, or container integration, to minimize scrutiny during code review.
Because the process operates under the developer’s existing user privileges, successful exploitation could lead to exposure of environment variables, source code, cloud credentials, SSH keys, API tokens, and locally stored Claude configuration. This interpretation aligns with general workspace-trust models used by development tools but researchers argue it fails to account for the distinction between viewing code and launching an autonomous coding agent. - Prevent CI runners from executing agentic tools against untrusted pull-request content and monitor configuration files for unexpected npx, Docker, shell, PowerShell, or network-execution entries.
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