Intel

CVE-2026-14541

mcp_toolbox_for_databases: Improper Authentication (CVE-2026-14541)

highEPSS 0.3%

Description

An authentication bypass and audience confusion vulnerability exists in the Google OAuth provider component of Google mcp-toolbox version 1.4.0. When a Google authService is initialized with mcpEnabled: true but lacks an explicitly defined audience or clientId, the ValidateMCPAuth pipeline for opaque tokens skips audience validation entirely. As a result, the toolbox will accept any valid Google OAuth access token—even those minted for unrelated ecosystem applications—granting unauthorized clients access to protected tools and data backends.

Source: NVD (NIST)cvelistv5

Affected products

The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

googlemcp_toolbox_for_databases

Metrics

XIEM Effective CVSS
8.0
Source: nvd-v4
EPSS percentile
15.4 %
Elevated — this CVE ranks above at least 10% of all CVEs scored today.
KEV status
—
Show all metrics
Severity
high
Priority score
65.59
Exploit maturity
no public PoC known
CVSS v3
7.5
CVSS v4
8.0
EPSS score
0.3 %
Low — model estimates < 1% exploitation likelihood.
Published
2026-07-31 01:48 UTC
CWE
CWE-287

Weakness classes (CWE)

  • CWE-287Class

    Improper Authentication

    When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.

    cwe.mitre.org →

References & sources

Reanalysis & status changes

Chronological NVD audit events for this CVE — reanalyses, CVSS updates, CPE diffs.

  1. Initial Analysis2026-08-08 00:06 UTC· nvd@nist.gov
    • CVSS V3.1: AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
    • CPE Configuration: OR *cpe:2.3:a:google:mcp_toolbox_for_databases:1.4.0:*:*:*:*:*:*:*
    • Reference Type: Google Inc.: https://github.com/googleapis/mcp-toolbox/pull/3450 Types: Issue Tracking, Patch
  2. CVE Modified2026-07-31 17:16 UTC· 134c704f-9b21-4f2e-91b3-4a467353bcc0
    • SSVC: {"id":"CVE-2026-14541","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"yes"},{"technical…
  3. New CVE Received2026-07-31 03:16 UTC· cve-coordination@google.com
    • Affected: mcp-toolbox
    • Description: An authentication bypass and audience confusion vulnerability exists in the Google OAuth provider component of Google mcp-toolbox version 1.4.0. When a Google authService is initialized with mcpEnabled: true but lacks an explicitly defined audience or clientId, the ValidateMCPAuth pipeline for opaque tokens skips audience validation entirely. As a result, the toolbox will accept any valid Google OAuth access token—even those minted for unrelated ecosystem applications—granting unauthorized clients access to protected tools and data backends.
    • CVSS V4.0: AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/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
    • CWE: CWE-287