Remote Code Execution in Cursor CLI via Cursor Agent MCP OAuth2 Communication

Summary

In the latest version of Cursor Agent CLI, when MCP uses OAuth authentication with an untrusted MCP server, an attacker can impersonate a malicious MCP server and return crafted, maliciously injected commands during the interaction process, leading to command injection and potential remote code execution.

Impact

If chained with an untrusted MCP service via OAuth, this command injection vulnerability could allow arbitrary code execution on the host by the agent. This can then be used to directly compromise the system by executing malicious commands with full user privileges.

Remediation

Fixed the command injection site.