---
id: CVE-2026-14541
title: >-
  An authentication bypass and audience confusion vulnerability exists in the
  Google OAuth provider component of Google mcp-toolbox version 1.4.0
summary: >-
  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 defin…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'
cwe:
  - CWE-287
vendor: google
product: mcp_toolbox_for_databases
affected:
  - mcp_toolbox_for_databases = 1.4.0
published: '2026-07-31'
updated: '2026-08-08'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-14541'
references:
  - url: 'https://github.com/googleapis/mcp-toolbox/pull/3450'
    label: cve-coordination@google.com
tags:
  - nvd
epss: 0.00234
epssPercentile: 0.14531
ingestedAt: '2026-08-08T14:22:57.238Z'
---

## Overview

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.

## Affected

- `mcp_toolbox_for_databases = 1.4.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.