CVE-2025-64340

FastMCP has a Command Injection vulnerability - Gemini CLI

State
Published
Severity
6.7 Medium
Published
Apr 3, 2026
Updated
Apr 3, 2026
Reserved
Oct 30, 2025

Read the record on cve.org

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.

Scores

CVSSScoreVectorSource
3.16.7 MediumCVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:HGitHub_M

Weaknesses

  • CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

Affected Products

ProductVersions
fastmcpjlowin
  • < 3.2.0Affected

References

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.