CVE-2026-14541 (GCVE-0-2026-14541)
Vulnerability from cvelistv5 – Published: 2026-07-31 01:48 – Updated: 2026-07-31 16:14
VLAI
EPSS
VEX
Title
Authentication Bypass and Audience Confusion in MCP Toolbox OAuth Provider
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 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.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-07-31 16:14 UTC
CWE
- CWE-287 - (Improper Authentication)
Assigner
References
1 reference
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| mcp-toolbox |
Affected:
1.4.0
(semver)
|
guessed |
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