Executive brief
ChrisChinchilla Vale-MCP is a tool used to integrate the Vale prose linter with the Model Context Protocol (MCP). A security flaw allows an attacker to execute unauthorized system commands by providing a specially crafted configuration path. This could lead to a complete takeover of the server or system running the software, potentially exposing sensitive data or disrupting operations.
Technical details
An OS command injection vulnerability (CWE-78) exists in ChrisChinchilla Vale-MCP up to version 0.1.0. The vulnerability is located in the HTTP Interface, specifically within the `src/index.ts` and `src/vale-runner.ts` files. The `config_path` argument in the `check_file` and `check_text` tool calls is passed unsanitized to sensitive sinks such as `exec` and `execAsync`. While some reports suggest a local attack vector, the technical analysis indicates that any user capable of invoking the MCP/HTTP endpoint can achieve arbitrary code execution with the privileges of the server process. As of the disclosure date, no official patch has been released by the vendor.
Affected products
- ChrisChinchilla Vale-MCP 0.1.0
Timeline
- 2026-03-17: other: Vulnerability reported to vendor
- 2026-03-22: disclosed: Public disclosure of exploit/PoC on GitHub
- 2026-04-06: advisory: CVE published