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CVE-2026-14541

Authentication Bypass and Audience Confusion in MCP Toolbox OAuth Provider

Published: Jul 31, 2026Updated: Aug 8, 2026 Sources: CVE List NVDCWE-287
7.5HIGH
NVD MITRE
EPSS Score
0.2%
Top 85.8%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
Not available

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:HI:NA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:NIntegrity
None
A:NAvailability
None
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Weaknesses

CWE-287

Affected Products

Google
commercial·USaka google llc, google inc
mcp-toolboxOn-prem
Mobile Apps / android-app
mcp toolbox for databasesOn-premDatabase
Databases / db-tooling

Exploitability

Official Patch Available
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Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

2 techniques
Initial Access
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References

https://github.com/googleapis/mcp-toolbox/pull/3450
github.com

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