FKIE_CVE-2026-116684

Vulnerability from fkie_nvd - Published: 2026-10-27 20:17 - Updated: 2026-10-27 20:17
Severity
6.8 (Medium) - CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
Summary
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, server-side bearer authentication configured through AuthSettings with token_verifier accepts a valid token issued for another service when the authorization server serves multiple resources and the TokenVerifier does not independently validate the aud audience. This resource-confusion flaw lets a token holder authenticate to the wrong MCP server and exercise that token's resulting access. This issue is fixed in versions 1.30.0 and 2.2.0.
References
security-advisories@github.comhttps://github.com/modelcontextprotocol/python-sdk/commit/0c9136841ff092987a20700ff9c2c9789bda2f40
security-advisories@github.comhttps://github.com/modelcontextprotocol/python-sdk/commit/8c2fa6eabacde869d75568e33b9d466b58c2f512
security-advisories@github.comhttps://github.com/modelcontextprotocol/python-sdk/pull/3447
security-advisories@github.comhttps://github.com/modelcontextprotocol/python-sdk/pull/3451
security-advisories@github.comhttps://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.30.0
security-advisories@github.comhttps://github.com/modelcontextprotocol/python-sdk/releases/tag/v2.2.0
security-advisories@github.comhttps://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-w4fh-qvv9-3v23
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "python-sdk",
          "vendor": "modelcontextprotocol",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 1.10.0, \u003c 1.30.0"
            },
            {
              "status": "affected",
              "version": "\u003e= 2.0.0, \u003c 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 1.10.0 until 1.30.0 and 2.2.0, server-side bearer authentication configured through AuthSettings with token_verifier accepts a valid token issued for another service when the authorization server serves multiple resources and the TokenVerifier does not independently validate the aud audience. This resource-confusion flaw lets a token holder authenticate to the wrong MCP server and exercise that token\u0027s resulting access. This issue is fixed in versions 1.30.0 and 2.2.0."
    }
  ],
  "id": "CVE-2026-116684",
  "lastModified": "2026-10-27T20:17:13.307",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 6.8,
          "baseSeverity": "MEDIUM",
          "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:N",
          "version": "3.1"
        },
        "exploitabilityScore": 1.6,
        "impactScore": 5.2,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-10-27T20:17:13.307",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/modelcontextprotocol/python-sdk/commit/0c9136841ff092987a20700ff9c2c9789bda2f40"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/modelcontextprotocol/python-sdk/commit/8c2fa6eabacde869d75568e33b9d466b58c2f512"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/modelcontextprotocol/python-sdk/pull/3447"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/modelcontextprotocol/python-sdk/pull/3451"
    },
    {
      "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-w4fh-qvv9-3v23"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-863"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}



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