CVE-2026-14538

MEDIUM
MEDIUM Priority: 0.01 BB Relevance: 61/100
Published: 2026-07-31 Modified: 2026-10-23 First seen: 2026-10-29 Status: active

Attack Surface

Network Low Complexity No Interaction Conf. Impact

CVSS Vector Breakdown

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

Description

An improper authorization and security-boundary bypass vulnerability in the bigquery-execute-sql tool component of Google mcp-toolbox versions 0.16.1 through 1.4.0 allows an authenticated attacker to bypass allowedDatasets validation checks. The toolbox relies on the BigQuery dry-run API to enforce dataset restrictions, but due to a fail-open logic flaw, it bypasses validation when the API returns an empty array for specialized constructs. This allows the attacker to extract structural DDL schemas for explicitly excluded datasets via INFORMATION_SCHEMA, and access downstream federated row data via EXTERNAL_QUERY connections.

Weakness Classification (2)

Affected Software (1)

VendorProductVersion
google mcp_toolbox_for_databases 0.16.1 – 1.4.0

References & Advisories (1)

Bug Bounty Relevance

61 / 100
✓ Network accessible
✓ Low complexity
✓ No user interaction

CVSS Score

5.7 / 10.0 v4.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/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

0.20%
Raw Score 0.002040
Percentile 10.4%
Date 2026-10-29

EPSS Trend

2026-10-29
0.00204
2026-10-28
0.00204

Intelligence Sources

nvd ref →