How severe is CVE-2026-14538?

CVE-2026-14538 has a CVSS 3.x base score of 7.7, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2026-14538 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (9th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-14538?

CVE-2026-14538 affects Google Mcp Toolbox For Databases. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-14538?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2026-14538 published?

CVE-2026-14538 was published on 2026-07-31 and last updated on 2026-08-08.

CVE-2026-14538

CVE-2026-14538 is a high-severity vulnerability in Google Mcp Toolbox For Databases with a CVSS 3.x base score of 7.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-285.

Key facts

Severity: High (CVSS 3.x base score 7.7)
CVSS v4: 5.7
EPSS exploit prediction: 0% (9th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-285
Affected product: Google Mcp Toolbox For Databases
Published: 2026-07-31
Last modified: 2026-08-08

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.

Frequently asked questions

What is CVE-2026-14538?: 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.
How severe is CVE-2026-14538?: CVE-2026-14538 has a CVSS 3.x base score of 7.7, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2026-14538 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (9th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-14538?: CVE-2026-14538 affects Google Mcp Toolbox For Databases. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-14538?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-14538 published?: CVE-2026-14538 was published on 2026-07-31 and last updated on 2026-08-08.

References

https://github.com/googleapis/mcp-toolbox/pull/3452

Affected products (1)

cpe:2.3:a:google:mcp_toolbox_for_databases:*:*:*:*:*:*:*:*

More vulnerabilities in Google Mcp Toolbox For Databases

CVE-2026-14537 — Critical (CVSS 9.8): Incorrect Authorization in the direct HTTP API tool invocation endpoint in Google mcp-toolbox versions v1.3.0 and…
CVE-2026-11720 — Critical (CVSS 9.1): A path traversal vulnerability exists in the HTTP tool URL builder of googleapis/mcp-toolbox. When constructing…
CVE-2026-11718 — Critical (CVSS 9.1): An authentication bypass vulnerability exists in the generic opaque token validation path (validateOpaqueToken) of…
CVE-2026-11717 — Critical (CVSS 9.1): An authentication bypass vulnerability exists in the generic opaque token validation path (validateOpaqueToken) of…
CVE-2026-11719 — High (CVSS 8.1): An authenticated authorization bypass vulnerability exists in MCP Toolbox for Databases due to missing scope…
CVE-2026-14541 — High (CVSS 7.5): An authentication bypass and audience confusion vulnerability exists in the Google OAuth provider component of Google…

All CVEs affecting Google Mcp Toolbox For Databases →

Other CWE-285 (Improper Authorization) vulnerabilities

CVE-2025-65041 — Critical (CVSS 10.0): Improper authorization in Microsoft Partner Center allows an unauthorized attacker to elevate privileges over a network.
CVE-2023-33189 — Critical (CVSS 10.0): Pomerium is an identity and context-aware access proxy. With specially crafted requests, incorrect authorization…
CVE-2022-2595 — Critical (CVSS 10.0): Improper Authorization in GitHub repository kromitgmbh/titra prior to 0.79.1.
CVE-2021-28799 — Critical (CVSS 10.0): An improper authorization vulnerability has been reported to affect QNAP NAS running HBS 3 (Hybrid Backup Sync. ) If…
CVE-2026-55166 — Critical (CVSS 9.9): Lemur manages TLS certificate creation. Prior to 1.9.2, authenticated users could influence an ACME authority acme_url…
CVE-2026-34048 — Critical (CVSS 9.9): Coolify is an open-source and self-hostable tool for managing servers, applications, and databases. Prior to…

Browse all CWE-285 (Improper Authorization) vulnerabilities →