CVE-2025-64340
MediumCVSS 6.7Exploitation Probability (EPSS)
Elevated risk51th percentile - higher than 51% of all known CVEs
Summary
A vulnerability in FastMCP before version 3.2.0. Server names containing shell metacharacters (e.g., &) can cause command injection on Windows during installation via fastmcp install claude-code or gemini-cli.
Risk Assessment
An attacker can exploit this to execute arbitrary commands on Windows, potentially leading to application compromise.
Recommendation
Upgrade FastMCP to version 3.2.0 or later.
Other vulnerabilities in FastMCP
See all- CVE-2026-32871Critical
In FastMCP prior to version 3.2.0, the _build_url() method in the RequestDirector class lacks URL encoding of path parameters. This allows an attacker to inject ../ sequences and perform a path traversal attack, enabling access to arbitrary internal endpoints.
- CVE-2026-27124Medium
In FastMCP prior to version 3.2.0, a Confused Deputy vulnerability was found in the OAuthProxy component. During GitHub OAuth integration, the server does not properly validate user consent, which combined with GitHub skipping the consent screen enables an attack.
- CVE-2025-69196Medium
In the FastMCP library before version 2.14.2, the server does not properly respect the resource parameter submitted by the client in the authorization and token request. The token is issued for the base_url passed to the OAuthProxy during initialization, not for the specific MCP server.
Original NVD description (English source)
FastMCP is the standard framework for building MCP applications. Prior to version 3.2.0, server names containing shell metacharacters (e.g., &) can cause command injection on Windows when passed to fastmcp install claude-code or fastmcp install gemini-cli. These install paths use subprocess.run() with a list argument, but on Windows the target CLIs often resolve to .cmd wrappers that are executed through cmd.exe, which interprets metacharacters in the flattened command string. This issue has been patched in version 3.2.0.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS