CVE-2025-64340
Last modified
CVE-2025-64340 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. 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. EPSS estimates a 0.75% chance of exploitation in the next 30 days.
Description
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.
Metrics
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Jlowin | Fastmcp | < 3.2.0 |
References
- https://github.com/PrefectHQ/fastmcp/pull/3522Issue Tracking, Patch
- https://github.com/PrefectHQ/fastmcp/security/advisories/GHSA-m8x7-r2rg-vh5gExploit, Patch, Vendor Advisory
- https://github.com/PrefectHQ/fastmcp/security/advisories/GHSA-m8x7-r2rg-vh5gExploit, Patch, Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
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