Modelcontextprotocol Python-Sdk vulnerabilities

CVE-2025-53366 [HIGH] CWE-248 CVE-2025-53366: The MCP Python SDK, called `mcp` on PyPI, is a Python implementation of the Model Context Protocol ( The MCP Python SDK, called `mcp` on PyPI, is a Python implementation of the Model Context Protocol (MCP). Prior to version 1.9.4, a validation error in the MCP SDK can cause an unhandled exception when processing malformed requests, resulting in service unavailability (500 errors) until manually restarted. Impact may vary depending on the deployment c

CVE-2025-66416 [HIGH] CWE-1188 CVE-2025-66416: The MCP Python SDK, called `mcp` on PyPI, is a Python implementation of the Model Context Protocol ( The MCP Python SDK, called `mcp` on PyPI, is a Python implementation of the Model Context Protocol (MCP). Prior to version 1.23.0, tThe Model Context Protocol (MCP) Python SDK does not enable DNS rebinding protection by default for HTTP-based servers. When an HTTP-based MCP server is run on localhost without authentication using FastMCP with streamab

CVE-2025-53365 [HIGH] CWE-248 CVE-2025-53365: The MCP Python SDK, called `mcp` on PyPI, is a Python implementation of the Model Context Protocol ( The MCP Python SDK, called `mcp` on PyPI, is a Python implementation of the Model Context Protocol (MCP). Prior to version 1.10.0, if a client deliberately triggers an exception after establishing a streamable HTTP session, this can lead to an uncaught ClosedResourceError on the server side, causing the server to crash and requiring a restart to resto

CVE-2026-52870 [HIGH] CWE-862 CVE-2026-52870: The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol (MC The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol (MCP). From 1.23.0 until 1.27.2, default handlers installed by server.experimental.enable_tasks() for tasks/list, tasks/get, tasks/result, and tasks/cancel operate only on task identifiers without recording the session that created each task, allowing any

CVE-2026-52869 [HIGH] CWE-639 CVE-2026-52869: The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol (MC The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol (MCP). Prior to 1.27.2, the SSE and stateful Streamable HTTP transports mcp.server.sse.SseServerTransport and mcp.server.streamable_http_manager.StreamableHTTPSessionManager route requests to existing sessions using only the session_id query parameter or M

CVE-2026-59950 [HIGH] CWE-346 CVE-2026-59950: The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol (MC The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol (MCP). Prior to 1.28.1, the deprecated mcp.server.websocket.websocket_server transport accepted WebSocket handshakes without applying Host or Origin header validation, leaving no SDK-level way to restrict which origins could connect to applications that ex