CVE-2026-14537 PUBLISHED

Authorization Bypass in MCP Toolbox Legacy HTTP Endpoints

Assigner: Google
Reserved: 03.07.2026 Published: 31.07.2026 Updated: 31.07.2026

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.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U
CVSS Score: 8.1

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	High	Confidentiality	None
Attack Complexity	Low	Integrity	High	Integrity	None
Attack Requirements	None	Availability	High	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

Product Status

Vendor	Google
Product	mcp-toolbox
Versions	Default: unaffected Version 1.3.0 is affected Version v1.4.0 is affected

Credits

HE WEI (ギカク) finder
David Carliez reporter

References

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

Problem Types

CWE-863 (Incorrect Authorization) CWE

Impacts

CAPEC-180 Exploiting Incorrectly Configured Access Control Security Levels