CVE-2026-14541

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Source

https://cve.org/CVERecord?id=CVE-2026-14541

Import Source

https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-14541.json

JSON Data

https://api.osv.dev/v1/vulns/CVE-2026-14541

Published

2026-07-31T01:48:39.019Z

Modified

2026-08-01T03:46:03.277636373Z

Severity

8.0 (High) CVSS_V4 - 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:U CVSS Calculator

Summary

Authentication Bypass and Audience Confusion in MCP Toolbox OAuth Provider

Details

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.

Database specific

{
    "cwe_ids": [
        "CWE-287"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/14xxx/CVE-2026-14541.json",
    "cna_assigner": "Google"
}

References

Affected packages

Git / github.com/googleapis/mcp-toolbox

Affected ranges

Type

GIT

Repo

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

Events

Introduced

d67cfbe8ddca5a50c9577ea11feaf5c94d0acace

Last affected

d67cfbe8ddca5a50c9577ea11feaf5c94d0acace

Database specific

{
    "source": "AFFECTED_FIELD",
    "extracted_events": [
        {
            "introduced": "1.4.0"
        },
        {
            "last_affected": "1.4.0"
        }
    ]
}

Affected versions

1.*

1.4.0

v1.*

v1.4.0

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-14541.json"