CVSS 3.1
7.8 highCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HCVE-2025-64340
High (7.8) in jlowin fastmcp. EPSS 0.7% chance of exploitation in the next 30 days. Fixed in fastmcp 3.2.0.
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.
Severity
- EPSS
- 0.7% chance of exploitation in the next 30 days; higher than 54% of CVEs (scores of 2026-10-31)
- CWE
- CWE-78
- Published
- Modified
- Record from
- the NVD, synced
Affected
- jlowin:fastmcp
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-m8x7-r2rg-vh5g | PyPI | fastmcp | <3.2.0 | 3.2.0 |
| PYSEC-2026-2475 | PyPI | fastmcp | <3.2.0 | 3.2.0 |