CVEvulnerability

CVE-2026-11717

9.3 CRITICAL Published 2026-06-18 Modified 2026-10-26 Official page ↗
Status
Analyzed
Published
2026-06-18
Last modified
2026-10-26
Assigner
[email protected]
CVSS 4.0 ([email protected])
9.3 CRITICAL — CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1 ([email protected])
9.1 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Weaknesses
CWE-287

Description

An authentication bypass vulnerability exists in the generic opaque token validation path (validateOpaqueToken) of googleapis/mcp-toolbox. When verifying an unparsed opaque token via an OAuth 2.0 introspection endpoint (RFC 7662), the toolbox decodes the response into an introspectResp struct where the Active field is declared as a pointer to a boolean (*bool). The code only explicitly rejects a token if the response contains a populated active field set to false (if introspectResp.Active != nil && !*introspectResp.Active). If an introspection endpoint responds with a payload that completely omits the mandatory active key, the internal variable remains nil, causing the conditional check to short-circuit. As a result, Toolbox accepts authorization tokens missing the "active" field, granting access to protected tools and underlying data sources.

Affected configurations

• google mcp toolbox for databases (>= 1.0.0 <= 1.3.0)

Related

Weakness · CWE (1)

  • CWE-287 Improper Authentication weakness

References