{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "1.4.0"
              },
              {
                "last_affected": "1.4.0"
              }
            ],
            "source": "AFFECTED_FIELD"
          },
          "events": [
            {
              "introduced": "d67cfbe8ddca5a50c9577ea11feaf5c94d0acace"
            },
            {
              "last_affected": "d67cfbe8ddca5a50c9577ea11feaf5c94d0acace"
            }
          ],
          "repo": "https://github.com/googleapis/mcp-toolbox",
          "type": "GIT"
        }
      ],
      "versions": [
        "1.4.0"
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Google",
    "cwe_ids": [
      "CWE-287"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/14xxx/CVE-2026-14541.json"
  },
  "details": "An authentication bypass and audience confusion vulnerability exists in the Google OAuth provider component of Google mcp-toolbox version 1.4.0. When a Google authService is initialized with mcpEnabled: true but lacks an explicitly defined audience or clientId, the ValidateMCPAuth pipeline for opaque tokens skips audience validation entirely. As a result, the toolbox will accept any valid Google OAuth access token—even those minted for unrelated ecosystem applications—granting unauthorized clients access to protected tools and data backends.",
  "id": "CVE-2026-14541",
  "modified": "2026-08-02T03:31:51.139043175Z",
  "published": "2026-07-31T01:48:39.019Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/14xxx/CVE-2026-14541.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-14541"
    },
    {
      "type": "FIX",
      "url": "https://github.com/googleapis/mcp-toolbox/pull/3450"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Authentication Bypass and Audience Confusion in MCP Toolbox OAuth Provider"
}