CVE-2025-64340

MEDIUM

6.7

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.

CVE Details

CVSS v3.1 Score6.7

SeverityMEDIUM

CVSS VectorCVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H

Attack VectorLOCAL

ComplexityHIGH

Privileges RequiredLOW

User InteractionREQUIRED

Published4/3/2026

Last Modified4/3/2026

Sourcenvd

Honeypot Sightings0

Weaknesses (CWE)

CWE-78

References

https://github.com/PrefectHQ/fastmcp/pull/3522(security-advisories@github.com)

https://github.com/PrefectHQ/fastmcp/security/advisories/GHSA-m8x7-r2rg-vh5g(security-advisories@github.com)

https://github.com/PrefectHQ/fastmcp/security/advisories/GHSA-m8x7-r2rg-vh5g(134c704f-9b21-4f2e-91b3-4a467353bcc0)

IOC Correlations

No correlations recorded

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