{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-116685", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-10-26T20:00:59.830Z", "datePublished": "2026-10-27T19:26:46.926Z", "dateUpdated": "2026-10-27T19:26:46.926Z"}, "containers": {"cna": {"title": "Model Context Protocol Python SDK: HTTP client transports followed cross-origin redirects carrying custom headers and bodies", "problemTypes": [{"descriptions": [{"cweId": "CWE-200", "lang": "en", "description": "CWE-200: Exposure of Sensitive Information to an Unauthorized Actor", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 5.9, "baseSeverity": "MEDIUM", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N", "version": "3.1"}}], "references": [{"name": "https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-5h93-6whr-6q8j", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-5h93-6whr-6q8j"}, {"name": "https://github.com/modelcontextprotocol/python-sdk/pull/3397", "tags": ["x_refsource_MISC"], "url": "https://github.com/modelcontextprotocol/python-sdk/pull/3397"}, {"name": "https://github.com/modelcontextprotocol/python-sdk/pull/3448", "tags": ["x_refsource_MISC"], "url": "https://github.com/modelcontextprotocol/python-sdk/pull/3448"}, {"name": "https://github.com/modelcontextprotocol/python-sdk/commit/2106335745563b2321b8c73fef2c12903d00aa6e", "tags": ["x_refsource_MISC"], "url": "https://github.com/modelcontextprotocol/python-sdk/commit/2106335745563b2321b8c73fef2c12903d00aa6e"}, {"name": "https://github.com/modelcontextprotocol/python-sdk/commit/c6762e821c527925f0b617db216d00fbd1d0bf99", "tags": ["x_refsource_MISC"], "url": "https://github.com/modelcontextprotocol/python-sdk/commit/c6762e821c527925f0b617db216d00fbd1d0bf99"}, {"name": "https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.30.0", "tags": ["x_refsource_MISC"], "url": "https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.30.0"}, {"name": "https://github.com/modelcontextprotocol/python-sdk/releases/tag/v2.2.0", "tags": ["x_refsource_MISC"], "url": "https://github.com/modelcontextprotocol/python-sdk/releases/tag/v2.2.0"}], "affected": [{"vendor": "modelcontextprotocol", "product": "python-sdk", "versions": [{"version": ">= 1.8.0, < 1.30.0", "status": "affected"}, {"version": ">= 2.0.0, < 2.2.0", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-10-27T19:26:46.926Z"}, "descriptions": [{"lang": "en", "value": "The Model Context Protocol Python SDK is the official Python SDK for Model Context Protocol servers and clients. From 1.8.0 until 1.30.0 and 2.2.0, streamable_http_client, streamablehttp_client, sse_client, ClientSessionGroup, OAuth, and create_mcp_http_client client paths enable follow_redirects and follow redirects to a different origin, forwarding caller-supplied custom credential headers and, for 307 or 308 responses, the request body. An attacker who can influence a trusted endpoint's redirect destination can receive that material. This issue is fixed in versions 1.30.0 and 2.2.0."}], "source": {"advisory": "GHSA-5h93-6whr-6q8j", "discovery": "UNKNOWN"}}}}

{}

{"affected": [{"affectedData": [{"product": "python-sdk", "vendor": "modelcontextprotocol", "versions": [{"status": "affected", "version": ">= 1.8.0, < 1.30.0"}, {"status": "affected", "version": ">= 2.0.0, < 2.2.0"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "The Model Context Protocol Python SDK is the official Python SDK for Model Context Protocol servers and clients. From 1.8.0 until 1.30.0 and 2.2.0, streamable_http_client, streamablehttp_client, sse_client, ClientSessionGroup, OAuth, and create_mcp_http_client client paths enable follow_redirects and follow redirects to a different origin, forwarding caller-supplied custom credential headers and, for 307 or 308 responses, the request body. An attacker who can influence a trusted endpoint's redirect destination can receive that material. This issue is fixed in versions 1.30.0 and 2.2.0."}], "id": "CVE-2026-116685", "lastModified": "2026-10-27T20:17:13.493", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 5.9, "baseSeverity": "MEDIUM", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N", "version": "3.1"}, "exploitabilityScore": 2.2, "impactScore": 3.6, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-10-27T20:17:13.493", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/modelcontextprotocol/python-sdk/commit/2106335745563b2321b8c73fef2c12903d00aa6e"}, {"source": "security-advisories@github.com", "url": "https://github.com/modelcontextprotocol/python-sdk/commit/c6762e821c527925f0b617db216d00fbd1d0bf99"}, {"source": "security-advisories@github.com", "url": "https://github.com/modelcontextprotocol/python-sdk/pull/3397"}, {"source": "security-advisories@github.com", "url": "https://github.com/modelcontextprotocol/python-sdk/pull/3448"}, {"source": "security-advisories@github.com", "url": "https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.30.0"}, {"source": "security-advisories@github.com", "url": "https://github.com/modelcontextprotocol/python-sdk/releases/tag/v2.2.0"}, {"source": "security-advisories@github.com", "url": "https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-5h93-6whr-6q8j"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-200"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[1.8.0,1.30.0)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[2.0.0,2.2.0)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "python-sdk", "source": "cna", "vendor": "modelcontextprotocol"}, "product": "python-sdk", "vendor": "modelcontextprotocol"}], "created": "2026-10-27T20:30:08.564558+00:00", "updated": "2026-10-27T20:30:08.564585+00:00", "vendors": ["modelcontextprotocol", "modelcontextprotocol$PRODUCT$python-sdk"]}