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TI-2026-10122 Aliases CVE-2026-11718GHSA-wcpr-6g7x-p44r

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 the toolbox validates an opaque token via an OAuth 2.0 introspection endpoint (RFC 7662), it decodes the response into an introspectResp struct. However, the subsequent claim-checking logic (validateClaims) evaluates the issuer condition as if a.issuer != "" && iss != "". If the external OAuth provider's introspection response omits the optional iss (issuer) field completely, the variable iss defaults to an empty string. This causes the conditional block to evaluate to false and be skipped silently. Consequently, the application accepts tokens issued by unauthorized or unintended third-party identity providers.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00185 8th 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-wcpr-6g7x-p44r
  • 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-wcpr-6g7x-p44r

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-wcpr-6g7x-p44r github.com/googleapis/mcp-toolbox (Go) Fixed in 1.4.0 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-11718
  2. 2026-10-03 Alias added: GHSA-wcpr-6g7x-p44r

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-2026-10121 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