{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-52869", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-06-08T21:44:27.363Z", "datePublished": "2026-07-15T20:06:23.604Z", "dateUpdated": "2026-07-15T20:06:23.604Z"}, "containers": {"cna": {"title": "MCP Python SDK: HTTP transports serve session requests without verifying the authenticated principal", "problemTypes": [{"descriptions": [{"cweId": "CWE-639", "lang": "en", "description": "CWE-639: Authorization Bypass Through User-Controlled Key", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 7.1, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L", "version": "3.1"}}], "references": [{"name": "https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-jpw9-pfvf-9f58", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-jpw9-pfvf-9f58"}, {"name": "https://github.com/modelcontextprotocol/python-sdk/pull/2690", "tags": ["x_refsource_MISC"], "url": "https://github.com/modelcontextprotocol/python-sdk/pull/2690"}, {"name": "https://github.com/modelcontextprotocol/python-sdk/pull/2719", "tags": ["x_refsource_MISC"], "url": "https://github.com/modelcontextprotocol/python-sdk/pull/2719"}, {"name": "https://github.com/modelcontextprotocol/python-sdk/commit/1abcca2408a6b50e10ec601181f63f9978705c00", "tags": ["x_refsource_MISC"], "url": "https://github.com/modelcontextprotocol/python-sdk/commit/1abcca2408a6b50e10ec601181f63f9978705c00"}, {"name": "https://github.com/modelcontextprotocol/python-sdk/commit/ce267b6fc515dc4efc1dc70b6975b16ff0feef0a", "tags": ["x_refsource_MISC"], "url": "https://github.com/modelcontextprotocol/python-sdk/commit/ce267b6fc515dc4efc1dc70b6975b16ff0feef0a"}, {"name": "https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.27.2", "tags": ["x_refsource_MISC"], "url": "https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.27.2"}], "affected": [{"vendor": "modelcontextprotocol", "product": "python-sdk", "versions": [{"version": "< 1.27.2", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-07-15T20:06:23.604Z"}, "descriptions": [{"lang": "en", "value": "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."}], "source": {"advisory": "GHSA-jpw9-pfvf-9f58", "discovery": "UNKNOWN"}}}}

{}

{}

{}

{}