CVE-2026-11717

Full vulnerability record from the local CVENow database.

Description

An authentication bypass vulnerability exists in the generic opaque token validation path (validateOpaqueToken) of googleapis/mcp-toolbox. When verifying an unparsed opaque token via an OAuth 2.0 introspection endpoint (RFC 7662), the toolbox decodes the response into an introspectResp struct where the Active field is declared as a pointer to a boolean (*bool). The code only explicitly rejects a token if the response contains a populated active field set to false (if introspectResp.Active != nil && !*introspectResp.Active). If an introspection endpoint responds with a payload that completely omits the mandatory active key, the internal variable remains nil, causing the conditional check to short-circuit. As a result, Toolbox accepts authorization tokens missing the "active" field, granting access to protected tools and underlying data sources.

Severity

CRITICAL

CVSS score

9.3 (v4.0)

Vulnerability status

Analyzed

Source identifier

[email protected]

Published

2026-06-18 14:17:20.013000

Last modified

2026-10-26 11:10:00.157000

View original CVE JSON

{
  "id": "CVE-2026-11717",
  "sourceIdentifier": "[email protected]",
  "published": "2026-06-18T14:17:20.013",
  "lastModified": "2026-10-26T11:10:00.157",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "An authentication bypass vulnerability exists in the generic opaque token validation path (validateOpaqueToken) of googleapis/mcp-toolbox.\n\nWhen verifying an unparsed opaque token via an OAuth 2.0 introspection endpoint (RFC 7662), the toolbox decodes the response into an introspectResp struct where the Active field is declared as a pointer to a boolean (*bool). The code only explicitly rejects a token if the response contains a populated active field set to false (if introspectResp.Active != nil && !*introspectResp.Active). If an introspection endpoint responds with a payload that completely omits the mandatory active key, the internal variable remains nil, causing the conditional check to short-circuit. As a result, Toolbox accepts authorization tokens missing the \"active\" field, granting access to protected tools and underlying data sources."
    },
    {
      "lang": "es",
      "value": "Una vulnerabilidad de omisión de autenticación existe en la ruta genérica de validación de tokens opacos (validateOpaqueToken) de googleapis/mcp-toolbox.\n\nAl verificar un token opaco no analizado a través de un endpoint de introspección de OAuth 2.0 (RFC 7662), la caja de herramientas decodifica la respuesta en una estructura introspectResp donde el campo Active se declara como un puntero a un booleano (bool). El código solo rechaza explícitamente un token si la respuesta contiene un campo activo poblado establecido en falso (if introspectResp.Active != nil && !introspectResp.Active). Si un endpoint de introspección responde con una carga útil que omite completamente la clave activa obligatoria, la variable interna permanece nil, lo que provoca que la verificación condicional se cortocircuite. Como resultado, Toolbox acepta tokens de autorización a los que les falta el campo ’active’, otorgando acceso a herramientas protegidas y fuentes de datos subyacentes."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "Google",
          "product": "MCP Toolbox for Databases (googleapis/mcp-toolbox)",
          "defaultStatus": "unaffected",
          "versions": [
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              "version": "1.0.0",
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              "versionType": "semver",
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            }
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  "metrics": {
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          "confidentialityRequirement": "NOT_DEFINED",
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          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "valueDensity": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "providerUrgency": "NOT_DEFINED"
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    "cvssMetricV31": [
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          "scope": "UNCHANGED",
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    "ssvcV203": [
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          "id": "CVE-2026-11717",
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          "role": "CISA Coordinator",
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  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
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  "configurations": [
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          "cpeMatch": [
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  "references": [
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      "url": "https://github.com/googleapis/mcp-toolbox/pull/3341",
      "source": "[email protected]",
      "tags": [
        "Patch",
        "Third Party Advisory"
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}