CVE-2026-14541

HIGH
MEDIUM Priority: 0.02 BB Relevance: 76/100
Published: 2026-07-31 Modified: 2026-10-23 First seen: 2026-10-29 Status: active

Attack Surface

Network Low Complexity No Auth No Interaction Conf. Impact Integ. Impact

CVSS Vector Breakdown

AV: Network
AC: Low
PR: None
UI: None
S: X
AT: None
VC: High
VI: High
VA: None

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.

Weakness Classification (1)

Affected Software (1)

VendorProductVersion
google mcp_toolbox_for_databases 1.4.0

References & Advisories (1)

Bug Bounty Relevance

76 / 100
✓ Network accessible
✓ No authentication
✓ Low complexity
✓ No user interaction

CVSS Score

8.0 / 10.0 v4.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS — Exploitation Probability

0.25%
Raw Score 0.002530
Percentile 16.8%
Date 2026-10-29

EPSS Trend

2026-10-29
0.00253
2026-10-28
0.00253

Intelligence Sources

nvd ref →