CVE-2026-52869

{"id": "CVE-2026-52869", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-52869", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "total"}], "version": "2.0.3", "timestamp": "2026-07-16T13:00:22.816039Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.1, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "HIGH", "availabilityImpact": "LOW", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 5.5, "exploitabilityScore": 1.6}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "modelcontextprotocol", "product": "python-sdk", "versions": [{"status": "affected", "version": "< 1.27.2"}]}]}], "published": "2026-07-15T20:17:38.427", "references": [{"url": "https://github.com/modelcontextprotocol/python-sdk/commit/1abcca2408a6b50e10ec601181f63f9978705c00", "tags": ["Patch"], "source": "security-advisories@github.com"}, {"url": "https://github.com/modelcontextprotocol/python-sdk/commit/ce267b6fc515dc4efc1dc70b6975b16ff0feef0a", "tags": ["Patch"], "source": "security-advisories@github.com"}, {"url": "https://github.com/modelcontextprotocol/python-sdk/pull/2690", "tags": ["Issue Tracking", "Patch"], "source": "security-advisories@github.com"}, {"url": "https://github.com/modelcontextprotocol/python-sdk/pull/2719", "tags": ["Issue Tracking", "Patch"], "source": "security-advisories@github.com"}, {"url": "https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.27.2", "tags": ["Release Notes"], "source": "security-advisories@github.com"}, {"url": "https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-jpw9-pfvf-9f58", "tags": ["Vendor Advisory"], "source": "security-advisories@github.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-639"}]}], "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."}], "lastModified": "2026-07-17T18:06:50.957", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:lfprojects:mcp_python_sdk:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "72E45D33-DB09-44B8-9007-066026CF9C2C", "versionEndExcluding": "1.27.2"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}