CVE-2025-64340
FastMCP has a Command Injection vulnerability - Gemini CLI
CVSS Score
6.7
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-78 |
| Vendor | jlowin |
| Product | fastmcp |
| Published | Apr 3, 2026 |
| Last Updated | Apr 3, 2026 |
Stay Ahead of the Next One
Get instant alerts for jlowin fastmcp
Be the first to know when new medium vulnerabilities affecting jlowin fastmcp are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
CVSS v3 Breakdown
CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H Attack Vector
Local
Attack Complexity
High
Privileges Required
Low
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Affected Versions
jlowin / fastmcp
< 3.2.0