CVE-2026-11717Network attack vector

Authentication bypass via omitted token activity flag

Published Jun 18, 2026 · Updated Jun 18, 2026

Authentication bypass in Google MCP Toolbox for Databases 1.0.0 through 1.3.0 allows remote attackers to access protected tools via opaque tokens. validateOpaqueToken decodes the introspection response into a pointer-valued Active field and rejects only a present false value, so an omitted active key is accepted. Exploitation requires opaque-token authentication with an introspection endpoint that returns a response lacking active, exposing the tools and their underlying data-source permissions.

CVSS severity9.3
Critical
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in Google MCP Toolbox for Databases 1.0.0 through 1.3.0 allows remote attackers to access protected tools via opaque tokens. validateOpaqueToken decodes the introspection response into a pointer-valued Active field and rejects only a present false value, so an omitted active key is accepted. Exploitation requires opaque-token authentication with an introspection endpoint that returns a response lacking active, exposing the tools and their underlying data-source permissions.

The record

CVE
CVE-2026-11717
Published
Jun 18, 2026
Updated
Jun 18, 2026
Vendor
Go standard library
Product
MCP Toolbox for Databases
Classifications
CWE-287, CAPEC-114, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.0.0 <=1.3.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Go standard library · MCP Toolbox for Databasesversion=1.0.0 <=1.3.0

Published CVSS scores

9.1NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
9.3Google Inc.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

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-287Improper Authentication
CAPEC-114Authentication Abuse
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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