CVE-2025-64340

HIGH EPSS 50.3%
Published Apr 3, 20262mo ago · Modified Jun 17, 20261w ago
7.8 CVSS 3.1
High
Find Similar
Published Apr 3, 2026 2mo ago
Last Modified Jun 17, 2026 1w ago

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.

CVSS Details

Base Score
7.8
Exploitability
1.8
Impact
5.9
Vector string
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required None
User Interaction Required
Scope Unchanged
Confidentiality High
Integrity High
Availability High

Threat Intelligence

EPSS Exploit Probability
50.3% percentile
Exploit & Patch Status
Public Exploit Known
Patch Available

Weaknesses 1

CWE-78 OS Command Injection Injection

Affected Products 1

VendorProductVersionRange
jlowinfastmcp* <3.2.0

References 2

  • github.com https://github.com/PrefectHQ/fastmcp/pull/3522
    Issue TrackingPatch
  • github.com https://github.com/PrefectHQ/fastmcp/security/advisories/GHSA-m8x7-r2rg-vh5g
    ExploitPatchVendor Advisory

Remediation

  • github.com https://github.com/PrefectHQ/fastmcp/pull/3522
    Issue TrackingPatch
  • github.com https://github.com/PrefectHQ/fastmcp/security/advisories/GHSA-m8x7-r2rg-vh5g
    ExploitPatchVendor Advisory