CVE-2026-14537: Authorization Bypass in MCP Toolbox Legacy HTTP Endpoints

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-31 · updated 2026-10-23
Weakness: CWE-863

Description

Incorrect Authorization in the direct HTTP API tool invocation endpoint in Google mcp-toolbox versions v1.3.0 and v1.4.0 allows an unauthenticated attacker to invoke tools protected by the scopeRequired feature via sending tool invocation requests through legacy HTTP endpoints when the --enable-api flag is active.

Affected products

Google MCP Toolbox for Databases (googleapis/mcp-toolbox): 1.3.0, 1.4.0

References

https://github.com/googleapis/mcp-toolbox/pull/3435

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