CVE-2026-11717

PUBLISHED
Published: 18 Jun 2026, 11:50
Last modified:18 Jun 2026, 12:23

Vulnerability Summary

Overall Risk (default)
high
70/100
CVSS Score
9.3 CRITICAL
v4.0 (cve.org)
EPSS Score
No data
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

18 Jun 2026, 11:50
Published
Vulnerability first disclosed
18 Jun 2026, 12:23
Last Modified
Vulnerability information updated

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.

CVSS Metrics

  • v4.0•CRITICAL•Score: 9.3CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Techniques & Countermeasures

  • CWE-287•Improper Authentication

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

Affected Systems

  • google•mcp toolbox for databases (googleapis/mcp-toolbox)

    ≥ 1.0.0, ≤ 1.3.0

References (1)