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CVE-2026-11719: MCP Toolbox for Databases: authenticated authorization bypass

highCVSS 4.0 8.6GHSA-5gf6-gc35-xjpc

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.

Published Jun 18, 2026 · Updated Jun 19, 2026

Affected packages

github.com/googleapis/mcp-toolbox

Ecosystem: Go
Affected: < 1.4.0
Fixed in: 1.4.0
Check: go list -m github.com/googleapis/mcp-toolbox

Advisory details

From the GitHub Advisory Database (CC BY 4.0).

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).

References

How this page is made: the data panel comes from the GitHub Advisory Database, CISA’s KEV catalog, the NVD and FIRST EPSS, and updates twice a day. No analysis has been written for this entry yet. Methodology

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