CVE-2026-116685

{
  "id": "CVE-2026-116685",
  "sourceIdentifier": "[email protected]",
  "published": "2026-10-27T20:17:13.493",
  "lastModified": "2026-10-28T15:24:56.033",
  "vulnStatus": "Deferred",
  "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."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "modelcontextprotocol",
          "product": "python-sdk",
          "versions": [
            {
              "version": ">= 1.8.0, < 1.30.0",
              "status": "affected"
            },
            {
              "version": ">= 2.0.0, < 2.2.0",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
          "baseScore": 5.9,
          "baseSeverity": "MEDIUM",
          "attackVector": "NETWORK",
          "attackComplexity": "HIGH",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "availabilityImpact": "NONE"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 3.6
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-200"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/modelcontextprotocol/python-sdk/commit/2106335745563b2321b8c73fef2c12903d00aa6e",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/modelcontextprotocol/python-sdk/commit/c6762e821c527925f0b617db216d00fbd1d0bf99",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/modelcontextprotocol/python-sdk/pull/3397",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/modelcontextprotocol/python-sdk/pull/3448",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.30.0",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/modelcontextprotocol/python-sdk/releases/tag/v2.2.0",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-5h93-6whr-6q8j",
      "source": "[email protected]"
    }
  ]
}