Server-side Request Forgery (SSRF)

Overview fastmcp is a The fast, Pythonic way to build MCP servers and clients. Affected versions of this package are vulnerable to Server-side Request Forgery SSRF in the buildurl function. An attacker can access unauthorized internal backend endpoints and perform actions with elevated privileges...

GHSA-VV7Q-7JX5-F767 FastMCP OpenAPI Provider has an SSRF & Path Traversal Vulnerability

Technical Description The OpenAPIProvider in FastMCP exposes internal APIs to MCP clients by parsing OpenAPI specifications. The RequestDirector class is responsible for constructing HTTP requests to the backend service. A critical vulnerability exists in the buildurl method. When an OpenAPI...

acpx-teams (=0.1.0), arifos (>=2026.2.22 <=2026.4.16) +58 more potentially affected by CVE-2026-27124 via fastmcp (>=3.0.0 <=3.1.1)

fastmcp PYPI version =3.0.0, =2026.2.22, =2026.3.13, =1.0.0, =0.56.0, =0.1.0, =0.3.2, =0.2.0, =0.3.0, =1.1.0, =0.0.1, =0.1.0, =0.5.12b18, =0.5.12b19 - efn-mcp =0.1.0 and more Source cves: CVE-2026-27124 Source advisory: SNYK:PYTHON-FASTMCP-15871030...

Unintended Proxy or Intermediary ('Confused Deputy')

Overview fastmcp is a The fast, Pythonic way to build MCP servers and clients. Affected versions of this package are vulnerable to Unintended Proxy or Intermediary 'Confused Deputy' in the OAuthProxy.handleidpcallback function. An attacker can gain unauthorized access to resources associated with...

aa-rag (=0.4.3), acex (>=3.0.0 <=5.28.0) +825 more potentially affected by CVE-2026-27124 via fastmcp (>=0.1.0 <=3.1.1)

fastmcp PYPI version =0.1.0, =3.0.0, =0.2.0, =0.1.0, =0.1.7, =2.1.7, =0.1.0, =1.0.0, =0.4.6, =0.1.0, =1.8.0, =0.1.1, =0.1.5 and more Source cves: CVE-2026-27124 Source advisory: OSV:GHSA-RWW4-4W9C-7733...

aa-rag (=0.4.3), acex (>=3.0.0 <=5.28.0) +825 more potentially affected by CVE-2025-64340 via fastmcp (>=0.1.0 <=3.1.1)

fastmcp PYPI version =0.1.0, =3.0.0, =0.2.0, =0.1.0, =0.1.7, =2.1.7, =0.1.0, =1.0.0, =0.4.6, =0.1.0, =1.8.0, =0.1.1, =0.1.5 and more Source cves: CVE-2025-64340 Source advisory: OSV:GHSA-M8X7-R2RG-VH5G...

acpx-teams (=0.1.0), arifos (>=2026.2.22 <=2026.4.16) +58 more potentially affected by CVE-2025-64340 via fastmcp (>=3.0.0 <=3.1.1)

fastmcp PYPI version =3.0.0, =2026.2.22, =2026.3.13, =1.0.0, =0.56.0, =0.1.0, =0.3.2, =0.2.0, =0.3.0, =1.1.0, =0.0.1, =0.1.0, =0.5.12b18, =0.5.12b19 - efn-mcp =0.1.0 and more Source cves: CVE-2025-64340 Source advisory: SNYK:PYTHON-FASTMCP-15871029...

Command Injection

Overview fastmcp is a The fast, Pythonic way to build MCP servers and clients. Affected versions of this package are vulnerable to Command Injection via the subprocess-backed install commands. An attacker can execute arbitrary commands with the privileges of the user running the process by...

FastMCP has a Command Injection vulnerability - Gemini CLI

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...

PT-2026-29413

Name of the Vulnerable Software and Affected Versions FastMCP versions prior to 3.2.0 Description FastMCP, a framework for building MCP applications, is susceptible to command injection on Windows systems when server names contain shell metacharacters, such as &. This occurs during the fastmcp...

Security Bulletin: Command Injection Vulnerability in FastMCP server_name Field Enables Arbitrary Command Execution on Windows affects watsonx.data

Summary FastMCP is the standard framework for building MCP applications. Versions prior to 2.13.0, a command-injection vulnerability lets any attacker who can influence the servername field of an MCP execute arbitrary OS commands on Windows hosts that run fastmcp install cursor. This can affect...

CVE-2025-69196

A flaw was found in FastMCP, a framework for building MCP applications. The server does not correctly process the resource parameter provided by the client during authorization and token requests. This can lead to security tokens being issued for an unintended base URL Uniform Resource Locator...

aenvironment (=0.1.7rc1), agent-mcp-server (=0.0.4.0) +256 more potentially affected by CVE-2025-69196 via fastmcp (>=2.0.0 <=2.14.1)

fastmcp PYPI version =2.0.0, =0.4.6, =1.8.0, =0.1.1, =3.2.0, =3.2.0, =4.2.2, =3.0.2, =0.1.0, =0.2.7, =1.0.0rc1, =0.1.0, =0.2.7, =0.3.1 and more Source cves: CVE-2025-69196 Source advisory: SNYK:PYTHON-FASTMCP-15674454...

Incorrect Authorization

Overview fastmcp is a The fast, Pythonic way to build MCP servers and clients. Affected versions of this package are vulnerable to Incorrect Authorization due to improper handling of the resource parameter in the authorization and token request processes. An attacker can gain unauthorized access ...

CVE-2025-69196

The GHSA advisory GHSA-5H2M-4Q8J-PQPJ describes a misconfiguration in FastMCP OAuth Proxy where the token issuer/audience are derived from the proxy’s base_url, causing access and refresh tokens to be issued without binding to the requested MCP server resource. This means tokens can be used on ot...

CVE-2025-69196 FastMCP OAuth Proxy token reuse across MCP servers

FastMCP is the standard framework for building MCP applications. Prior to version 2.14.2, the server does not properly respect the resource parameter submitted by the client in the authorization and token request. Instead of issuing the token explicitly for the MCP server, the token is issued for...

CVE-2025-69196 FastMCP OAuth Proxy token reuse across MCP servers

FastMCP is the standard framework for building MCP applications. Prior to version 2.14.2, the server does not properly respect the resource parameter submitted by the client in the authorization and token request. Instead of issuing the token explicitly for the MCP server, the token is issued for...

CVE-2025-69196 FastMCP OAuth Proxy token reuse across MCP servers

FastMCP is the standard framework for building MCP applications. Prior to version 2.14.2, the server does not properly respect the resource parameter submitted by the client in the authorization and token request. Instead of issuing the token explicitly for the MCP server, the token is issued for...

GHSA-5H2M-4Q8J-PQPJ FastMCP OAuth Proxy token reuse across MCP servers

While testing the OAuth Proxy implementation, it was noticed that the server does not properly respect the resource parameter submitted by the client in the authorization and token request. Instead of issuing the token explicitly for this MCP server, the token is issued for the baseurl passed to...

aenvironment (=0.1.7rc1), agent-mcp-server (=0.0.4.0) +301 more potentially affected by CVE-2025-69196 via fastmcp (>=0.1.0 <=2.14.1)

fastmcp PYPI version =0.1.0, =1.0.0, =0.4.6, =1.8.0, =0.1.1, =3.2.0, =3.2.0, =4.2.2, =3.0.2, =0.1.0, =0.2.7, =1.0.0rc1, =0.1.0, =0.1.1 - arthub-mcp-server =0.2.0 and more Source cves: CVE-2025-69196 Source advisory: OSV:GHSA-5H2M-4Q8J-PQPJ...