FastMCP OpenAPI Provider has an SSRF & Path Traversal Vulnerability

Technical DescriptionThe 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...

PYSEC-2026-338 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...

PT-2026-53429

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 build url method. When an OpenAPI...

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 OpenAP...

CVE-2026-32871

FastMCP is a Pythonic way to build MCP servers and clients. Prior to version 3.2.0, 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 vulnerabilit...

CVE-2026-32871 FastMCP OpenAPI Provider has an SSRF & Path Traversal Vulnerability

FastMCP is a Pythonic way to build MCP servers and clients. Prior to version 3.2.0, 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 vulnerabilit...

CVE-2026-32871 FastMCP OpenAPI Provider has an SSRF & Path Traversal Vulnerability

FastMCP is a Pythonic way to build MCP servers and clients. Prior to version 3.2.0, 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 vulnerabilit...

CVE-2026-32871

CVE-2026-32871 affects FastMCP’s OpenAPIProvider in the FastMCP package (prior to 3.2.0). The root cause is that the _build_url() function substitutes path parameters directly into the URL without URL-encoding, and then urllib.parse.urljoin() interprets any embedded “../” as a directory traversal...

CVE-2026-32871

FastMCP is a Pythonic way to build MCP servers and clients. Prior to version 3.2.0, 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 vulnerabilit...

CVE-2026-32871 FastMCP OpenAPI Provider has an SSRF & Path Traversal Vulnerability

FastMCP is a Pythonic way to build MCP servers and clients. Prior to version 3.2.0, 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 vulnerabilit...

PT-2026-29424

Name of the Vulnerable Software and Affected Versions FastMCP versions affected versions not specified Description The OpenAPIProvider in FastMCP is susceptible to an authenticated Server-Side Request Forgery SSRF vulnerability due to insufficient URL encoding of path parameters. Specifically, th...