MCP Toolbox for Databases: authenticated authorization bypass
HighCVE-2026-11719 · Published Jun 18, 2026 · updated Jun 25, 2026
Affected versions
| Package | Affected | Fixed in |
|---|---|---|
| github.com/googleapis/mcp-toolbox Go | < 1.4.0 | 1.4.0 |
Details and references
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).
- CVSS 4.0
- 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
- Severity from
- GitHub (reviewed advisory)
- Weakness
- CWE-862
- Also known as
- CVE-2026-11719, GO-2026-5144
More mcp-toolbox advisories
All| Date | Advisory | Severity | Fixed in |
|---|---|---|---|
| Jun 18 | googleapis/mcp-toolbox: authentication bypass vulnerability in the generic opaque token validation path (validateOpaqueToken) CVE-2026-11717Criticalfixed in 1.4.0 | Critical | 1.4.0 |
| Jun 18 | googleapis/mcp-toolbox: authentication bypass vulnerability in the generic opaque token validation path (validateOpaqueToken) CVE-2026-11718Criticalfixed in 1.4.0 | Critical | 1.4.0 |
| Jun 13 | MCP Toolbox for Databases has an Origin Validation Error CVE-2026-11624Criticalfixed in 0.25.0 | Critical | 0.25.0 |
| Jun 29 | MCP Toolbox HTTP tool path parameters allow traversal to unintended endpoints CVE-2026-11720Critical9.1fixed in 1.3.0 | Critical9.1 | 1.3.0 |
| May 28 | MCP Toolbox for Databases vulnerable to DNS rebinding attacks CVE-2026-9739Criticalfixed in 1.2.0 | Critical | 1.2.0 |