GHSA-wcjj-9m6g-2fr2 — functype-mcp-server: MCP `set_functype_version` Package Alias RCE via Unsanitized pnpm install + Dynamic Import

Affected: npm: functype-mcp-server

## MCP `set_functype_version` Package Alias RCE via Unsanitized pnpm install + Dynamic Import

### Summary

The `set_functype_version` MCP tool in `functype-mcp-server` accepts an unconstrained `version` string, interpolates it directly into an npm package specifier (`functype@<version>`), and installs it via `pnpm add` without any validation. Because npm/pnpm package specifiers support `file:`, `npm:`, and other alias syntaxes, an attacker who can send an MCP `tools/call` request to this tool can cause the server to install an arbitrary local or remote package as `functype`. Immediately after installation, the server calls `initDocsData(true)`, which dynamically imports `functype/cli` from the newly installed location, executing attacker-controlled JavaScript in the MCP server process. This results in full Remote Code Execution (RCE) with the privileges of the server process — full confidentiality, integrity, and availability impact (CVSS 7.8 High).

### Details

The vulnerable code is in `packages/mcp-server/src/index.ts`. The `set_functype_version` tool is registered at line 115 and is enabled by default (no authentication required in stdio mode).

**Source (user input accepted without validation):** ```ts // packages/mcp-server/src/index.ts:119-121 parameters: z.object({ version: z.string().describe('The functype version to install (e.g., "0.46.0", "latest", "^0.45.0")'), }), ``` Only `z.string()` validation is applied — no semver format check, no allowlist for dist-ta…

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GHSA-wcjj-9m6g-2fr2 — functype-mcp-server: MCP `set_functype_version` Package Alias RCE via Unsanitized pnpm install + Dynamic Import