{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-116686",
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "state": "PUBLISHED",
        "assignerShortName": "GitHub_M",
        "dateReserved": "2026-10-26T20:00:59.830Z",
        "datePublished": "2026-10-27T19:29:16.001Z",
        "dateUpdated": "2026-10-28T16:13:45.473Z"
    },
    "containers": {
        "cna": {
            "title": "Model Context Protocol Python SDK: Client fetched server-chosen $ref URLs while validating tool results against output schemas",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-918",
                            "lang": "en",
                            "description": "CWE-918: Server-Side Request Forgery (SSRF)",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "attackComplexity": "LOW",
                        "attackVector": "NETWORK",
                        "availabilityImpact": "HIGH",
                        "baseScore": 6.5,
                        "baseSeverity": "MEDIUM",
                        "confidentialityImpact": "NONE",
                        "integrityImpact": "NONE",
                        "privilegesRequired": "NONE",
                        "scope": "UNCHANGED",
                        "userInteraction": "REQUIRED",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H",
                        "version": "3.1"
                    }
                }
            ],
            "references": [
                {
                    "name": "https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-rwrf-2pqf-9j8j",
                    "tags": [
                        "x_refsource_CONFIRM"
                    ],
                    "url": "https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-rwrf-2pqf-9j8j"
                },
                {
                    "name": "https://github.com/modelcontextprotocol/python-sdk/pull/3394",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/modelcontextprotocol/python-sdk/pull/3394"
                },
                {
                    "name": "https://github.com/modelcontextprotocol/python-sdk/pull/3396",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/modelcontextprotocol/python-sdk/pull/3396"
                },
                {
                    "name": "https://github.com/modelcontextprotocol/python-sdk/commit/5ebdfed4060d8e5b11b8e2348f86bad4d1fb8836",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/modelcontextprotocol/python-sdk/commit/5ebdfed4060d8e5b11b8e2348f86bad4d1fb8836"
                },
                {
                    "name": "https://github.com/modelcontextprotocol/python-sdk/commit/6705402e246dc4eb1fcdf4d9902b78d3c9c36e1b",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/modelcontextprotocol/python-sdk/commit/6705402e246dc4eb1fcdf4d9902b78d3c9c36e1b"
                },
                {
                    "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": ">= 1.10.0, < 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": "2026-10-27T19:29:16.001Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "The Model Context Protocol Python SDK is the official Python SDK for Model Context Protocol servers and clients. From 1.10.0 until 1.30.0 and 2.2.0, ClientSession, ClientSessionGroup, and Client tool calls validate server-declared outputSchema documents with jsonschema's default resolver, causing an unresolved $ref value to fetch an HTTP, HTTPS, or file URL from the client's network and filesystem context. A server can trigger blind requests or local-file reads and can stall every session in the process because resolution runs synchronously on the event loop without a timeout. This issue is fixed in versions 1.30.0 and 2.2.0."
                }
            ],
            "source": {
                "advisory": "GHSA-rwrf-2pqf-9j8j",
                "discovery": "UNKNOWN"
            }
        },
        "adp": [
            {
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-10-28T14:34:36.544931Z",
                                "id": "CVE-2026-116686",
                                "options": [
                                    {
                                        "Exploitation": "none"
                                    },
                                    {
                                        "Automatable": "no"
                                    },
                                    {
                                        "Technical Impact": "partial"
                                    }
                                ],
                                "role": "CISA Coordinator",
                                "version": "2.0.3"
                            }
                        }
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2026-10-28T16:13:45.473Z"
                }
            }
        ]
    }
}