8.0
High
CVE-2026-14541 An authentication bypass and audience confusion vulnerability exists in the Google OAuth provider component of Google…
Description
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 products and versions
| Product | Affected versions | Fixed in |
|---|---|---|
| mcp-toolbox | 1.4.0 | No fix stated |
Other CVEs of mcp-toolbox
The 5 CVEs of mcp-toolbox →
CVE-2026-14540
A Server-Side Request Forgery (SSRF) vulnerability exists in the generic HTTP source and tool components of Google…
8.0
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CVE-2026-14539
An allocation of resources without limits vulnerability in the HTTP handler component of Google mcp-toolbox versions…
6.6
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CVE-2026-14538
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5.7
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CVE-2026-14537
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8.1
High