CVE-2025-64340
FastMCP has a Command Injection vulnerability - Gemini CLI
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.
INFO
Published Date :
April 3, 2026, 4:16 p.m.
Last Modified :
July 24, 2026, 9:10 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | MEDIUM | MITRE-CVE | ||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Upgrade FastMCP to version 3.2.0 or a newer version.
- Avoid using shell metacharacters in server names.
- Validate all user inputs for server names.
- Review subprocess usage for shell metacharacter handling.
Public PoC/Exploit Available at Github
CVE-2025-64340 has a 3 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2025-64340.
| URL | Resource |
|---|---|
| https://github.com/PrefectHQ/fastmcp/pull/3522 | Issue Tracking Patch |
| https://github.com/PrefectHQ/fastmcp/security/advisories/GHSA-m8x7-r2rg-vh5g | Exploit Patch Vendor Advisory |
| https://github.com/PrefectHQ/fastmcp/security/advisories/GHSA-m8x7-r2rg-vh5g | Exploit Patch Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-64340 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-64340
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
None
The Project shares all information on MCP related CVE's published
mcp mcp-security mcp-cve
NotebookLM MCP CLI - Access NotebookLM via Claude with security fixes and FastMCP 1.0 compatibility
Python
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2025-64340 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2025-64340 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Jul. 24, 2026
Action Type Old Value New Value Added Translation Title: fastmcp de jlowin, Description: FastMCP es el framework estándar para construir aplicaciones MCP. Antes de la versión 3.2.0, los nombres de servidor que contienen metacaracteres de shell (p. ej., &) pueden causar inyección de comandos en Windows cuando se pasan a fastmcp install claude-code o fastmcp install gemini-cli. Estas rutas de instalación usan subprocess.run() con un argumento de lista, pero en Windows las CLI objetivo a menudo se resuelven en wrappers .cmd que se ejecutan a través de cmd.exe, que interpreta los metacaracteres en la cadena de comandos aplanada. Este problema ha sido parcheado en la versión 3.2.0. -
CVE Modified by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'jlowin', 'product': 'fastmcp', 'versions': [{'status': 'affected', 'version': '< 3.2.0'}]}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2025-64340', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-04-03T16:11:50.768330Z'} -
Initial Analysis by [email protected]
Apr. 21, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Added CPE Configuration OR *cpe:2.3:a:jlowin:fastmcp:*:*:*:*:*:*:*:* versions up to (excluding) 3.2.0 Added Reference Type GitHub, Inc.: https://github.com/PrefectHQ/fastmcp/pull/3522 Types: Issue Tracking, Patch Added Reference Type GitHub, Inc.: https://github.com/PrefectHQ/fastmcp/security/advisories/GHSA-m8x7-r2rg-vh5g Types: Exploit, Patch, Vendor Advisory Added Reference Type CISA-ADP: https://github.com/PrefectHQ/fastmcp/security/advisories/GHSA-m8x7-r2rg-vh5g Types: Exploit, Patch, Vendor Advisory -
New CVE Received by [email protected]
Apr. 03, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H Added CWE CWE-78 Added Reference https://github.com/PrefectHQ/fastmcp/pull/3522 Added Reference https://github.com/PrefectHQ/fastmcp/security/advisories/GHSA-m8x7-r2rg-vh5g -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Apr. 03, 2026
Action Type Old Value New Value Added Reference https://github.com/PrefectHQ/fastmcp/security/advisories/GHSA-m8x7-r2rg-vh5g