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TI-2026-10121 Aliases CVE-2026-11717GHSA-8fcc-w5hv-4gxv

Improper authentication in Google MCP Toolbox for Databases

Priority MEDIUM 47CWE-287Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Security bypass
Confidentiality · integrity · availability
High · High · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-287.

Summary

An authentication bypass vulnerability exists in the generic opaque token validation path (validateOpaqueToken) of googleapis/mcp-toolbox. When verifying an unparsed opaque token via an OAuth 2.0 introspection endpoint (RFC 7662), the toolbox decodes the response into an introspectResp struct where the Active field is declared as a pointer to a boolean (*bool). The code only explicitly rejects a token if the response contains a populated active field set to false (if introspectResp.Active != nil && !*introspectResp.Active). If an introspection endpoint responds with a payload that completely omits the mandatory active key, the internal variable remains nil, causing the conditional check to short-circuit. As a result, Toolbox accepts authorization tokens missing the "active" field, granting access to protected tools and underlying data sources.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00176 7th percentileScored 2026-11-07
Fix Fixed github.com/googleapis/mcp-toolbox (Go): 1.4.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
GoogleMCP Toolbox for Databases (googleapis/mcp-toolbox)1.0.0 – 1.3.0—No fix listedCNA
—github.com/googleapis/mcp-toolbox (Go)before 1.4.01.4.0Patch availableGHSA-8fcc-w5hv-4gxv
  • MCP Toolbox for Databases (googleapis/mcp-toolbox) VendorGoogle Affected 1.0.0 – 1.3.0 Fixed in — No fix listed CNA
  • github.com/googleapis/mcp-toolbox (Go) Vendor— Affected before 1.4.0 Fixed in 1.4.0 Patch available GHSA-8fcc-w5hv-4gxv

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:google:mcp_toolbox_for_databases:*:*:*:*:*:*:*:*1.0.0 – 1.3.0VulnerableGoogle
  • cpe:2.3:a:google:mcp_toolbox_for_databases:*:*:*:*:*:*:*:* Versions 1.0.0 – 1.3.0 Vulnerable ·Google

Remediation

  • Fix · GHSA-8fcc-w5hv-4gxv github.com/googleapis/mcp-toolbox (Go) Fixed in 1.4.0 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-11717
  2. 2026-10-03 Alias added: GHSA-8fcc-w5hv-4gxv

References

Patch 1

Advisory 1

Other 1

  • TI-2026-10124 Path Traversal in googleapis/mcp-toolbox HTTP Tool URL Builder CVSS 4.0CRITICAL 9.3
  • TI-2026-10122 Improper authentication in Google MCP Toolbox for Databases CVSS 4.0CRITICAL 9.3
  • TI-2026-12267 Authorization Bypass in MCP Toolbox Legacy HTTP Endpoints CVSS 4.0HIGH 8.1
  • TI-2026-12271 Authentication Bypass and Audience Confusion in MCP Toolbox OAuth Provider CVSS 4.0HIGH 8.0
  • TI-2026-12270 Server-Side Request Forgery via Unrestricted HTTP Redirection in MCP Toolbox CVSS 4.0HIGH 8.0
  • TI-2026-13310 SQL Injection and Security Boundary Bypass in googleapis/mcp-toolbox CVSS 4.0HIGH 8.6
See all 10 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences