CVE-2026-11719

Authenticated Authorization Bypass via Old Protocol Versions in MCP Toolbox for Databases

Published Jun 18, 2026 CVSS 4.0 · 8.6 High EPSS < 1% KEV · Not listed
Description
An authenticated authorization bypass vulnerability exists in MCP Toolbox for Databases due to missing scope enforcement across older protocol handlers.

While the 2025-11-25 protocol version handler correctly enforces per-tool restrictions defined by scopesRequired, older supported protocol versions (2025-06-18, 2025-03-26, and 2024-11-05) omit this check. An authenticated client with low-privilege tokens (e.g., read) can bypass the intended per-tool scope restrictions and execute high-privilege tools (e.g., admin) simply by specifying an older protocol version in the MCP-Protocol-Version header, or by omitting the header entirely (which causes the server to default to the vulnerable 2024-11-05 handler).

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-5gf6-gc35-xjpc MCP Toolbox for Databases: authenticated authorization bypass
History
Type Values Removed Values Added
CPEs cpe:2.3:a:google:mcp_toolbox_for_databases:1.3.0:*:*:*:*:*:*:*
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N'}

Type Values Removed Values Added
First Time appeared Google
Google mcp Toolbox For Databases
Vendors & Products Google
Google mcp Toolbox For Databases
Type Values Removed Values Added
Title Authenticated Authorization Bypass via Old Protocol Versions in MCP Toolbox for Databases
Type Values Removed Values Added
Description An authenticated authorization bypass vulnerability exists in MCP Toolbox for Databases due to missing scope enforcement across older protocol handlers. While the 2025-11-25 protocol version handler correctly enforces per-tool restrictions defined by scopesRequired, older supported protocol versions (2025-06-18, 2025-03-26, and 2024-11-05) omit this check. An authenticated client with low-privilege tokens (e.g., read) can bypass the intended per-tool scope restrictions and execute high-privilege tools (e.g., admin) simply by specifying an older protocol version in the MCP-Protocol-Version header, or by omitting the header entirely (which causes the server to default to the vulnerable 2024-11-05 handler).
Weaknesses CWE-862
References
Metrics cvssV4_0

{'score': 8.6, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Google
Published
Updated
Jun 18, 2026, 1:53 PM
Reserved
Jun 9, 2026, 12:53 AM
Status
Analyzed
Published
Jun 18, 2026, 2:17 PM
Modified
Oct 26, 2026, 11:10 AM