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 Mcp-Session-Id header without verifying the authenticated principal that created the session, allowing a different bearer-token-authenticated client
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 Mcp-Session-Id header without verifying the authenticated principal that created the session, allowing a different bearer-token-authenticated client with a known session ID to inject JSON-RPC messages into that session. This issue is fixed in version 1.27.2.
왜 이 VPI인가 (설명가능 · 실험적)
VPI 산정 기준
| 영향도 | 71.00 |
| 악용 신호(추가 악용신호 없음) | ×1.00 |
| VPI | 71.00 |
VPI 공식 vpi-v1 기준
| 소스 | CVSS 버전 | 기본 점수 | 심각도 | 벡터 문자열 | 평가일 |
|---|---|---|---|---|---|
| OSV3rd | 3.1 | 7.1 | HIGH | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L | 2026. 07. 17. |
| NVDNIST | 3.1 | 7.1 |
| CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L |
| 2026. 07. 16. |