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.
Metrics
Affected Vendors & Products
References
| Link | Providers |
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| https://github.com/googleapis/mcp-toolbox/pull/3452 |
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History
Sun, 02 Aug 2026 21:00:00 +0000
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Google
Google mcp-toolbox |
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| Vendors & Products |
Google
Google mcp-toolbox |
Fri, 31 Jul 2026 17:30:00 +0000
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| Metrics |
ssvc
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Fri, 31 Jul 2026 02:00:00 +0000
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| 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. | |
| Title | BigQuery Dataset Allowlist Bypass via Metadata Dry-Run in MCP Toolbox | |
| Weaknesses | CWE-285 CWE-863 |
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| References |
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| Metrics |
cvssV4_0
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Status: PUBLISHED
Assigner: Google
Published: 2026-07-31T01:42:29.707Z
Updated: 2026-07-31T16:09:31.250Z
Reserved: 2026-07-03T02:06:17.583Z
Link: CVE-2026-14538
Updated: 2026-07-31T16:09:23.644Z
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