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SCA: security update for github.com/googleapis/mcp-toolbox (GHSA-wcpr-6g7x-p44r)

critical Tenable Cloud Security Plugin ID 443609

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

 - An authentication bypass vulnerability exists in the generic opaque token validation path
 (validateOpaqueToken) of googleapis/mcp-toolbox. When the toolbox validates an opaque token via an OAuth
 2.0 introspection endpoint (RFC 7662), it decodes the response into an introspectResp struct. However, the
 subsequent claim-checking logic (validateClaims) evaluates the issuer condition as if a.issuer != "" &&
 iss != "". If the external OAuth provider's introspection response omits the optional iss (issuer) field
 completely, the variable iss defaults to an empty string. This causes the conditional block to evaluate to
 false and be skipped silently. Consequently, the application accepts tokens issued by unauthorized or
 unintended third-party identity providers. (CVE-2026-11718)

Solution

Update the github.com/googleapis/mcp-toolbox library and its related packages to version 1.4.0 or later.

See Also

https://github.com/advisories/GHSA-wcpr-6g7x-p44r

Plugin Details

Severity: Critical

ID: 443609

Version: Revision 1.3

Type: Local

Family: SCA Checks

Published: 6/19/2026

Updated: 7/2/2026

Supported Sensors: Tenable Cloud Security, Tenable Self-Hosted Container Security

Risk Information

VPR

Risk Factor: Medium

Score: 4.3

Percentile: 53.61

Vendor

Vendor Severity: Critical

CVSS v2

Risk Factor: Medium

Base Score: 6.4

Temporal Score: 4.7

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:N

CVSS Score Source: CVE-2026-11718

CVSS v3

Risk Factor: Critical

Base Score: 9.1

Temporal Score: 7.9

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

CVSS v4

Risk Factor: Critical

Base Score: 9.3

Threat Score: 8

Threat Vector: CVSS:4.0/E:U

Vector: 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

Vulnerability Information

Exploit Ease: No known exploits are available

Patch Publication Date: 6/18/2026

Vulnerability Publication Date: 6/18/2026

Reference Information

CVE: CVE-2026-11718

cwe: CWE-287