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.
CVSS breakdown
CVSS 4.0
Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
Low
User Interaction
None
Confidentiality (Vulnerable System)
High
Integrity (Vulnerable System)
None
Availability (Vulnerable System)
None
Confidentiality (Subsequent System)
High
Integrity (Subsequent System)
None
Availability (Subsequent System)
None
E
Unchanged
CVSS 3.1
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None
Affected products
- Google / mcp-toolbox0.16.1 – 1.4.0
- Google / MCP Toolbox for Databases0.16.1 – 1.4.0
References
Updated 5m ago · 8 sources