Vulnerabilities in pkg:golang/github.com/googleapis/mcp-toolbox

PACKAGE
Advisory Identifier: GHSA-vwxw-jrg6-9jxv
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Advisory Summary

CVE-2026-11720 is a CRITICAL (CVSS 9.1) mcp toolbox http tool path vulnerability (CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')) affecting Github.com/googleapis/mcp toolbox libraries in the Go ecosystem. The issue involves mcp toolbox http tool path parameters allow traversal to unintended endpoints. Remediation is available by upgrading affected packages to version 1.3.0.

6 Known Advisory Record(s)
Package Vulnerability Intelligence

pkg:golang/github.com/googleapis/mcp-toolbox

6 Known Advisory Record(s)

Vulnerability advisories affecting package pkg:golang/github.com/googleapis/mcp-toolbox. Select an advisory below to view technical details or fixes.

Advisory ID CVE / NVD Severity Summary
GHSA-vwxw-jrg6-9jxv CVE-2026-11720 CRITICAL MCP Toolbox HTTP tool path parameters allow traversal to unintended endpoints
GHSA-76g7-m3xw-x9gr CVE-2026-11624 CRITICAL MCP Toolbox for Databases has an Origin Validation Error
GHSA-7pf3-8xx7-rvhf CVE-2026-9739 CRITICAL MCP Toolbox for Databases vulnerable to DNS rebinding attacks
GHSA-5gf6-gc35-xjpc CVE-2026-11719 HIGH MCP Toolbox for Databases: authenticated authorization bypass
GHSA-wcpr-6g7x-p44r CVE-2026-11718 CRITICAL googleapis/mcp-toolbox: authentication bypass vulnerability in the generic opaque token validation path (validateOpaqueToken)
GHSA-8fcc-w5hv-4gxv CVE-2026-11717 CRITICAL googleapis/mcp-toolbox: authentication bypass vulnerability in the generic opaque token validation path (validateOpaqueToken)

CVE-2026-11720 at a Glance

CVE Identifier CVE-2026-11720
GHSA Identifier GHSA-vwxw-jrg6-9jxv
Severity CRITICAL
CVSS v3.1 Base Score 9.1
CWE Classification CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Affected Product Github.com/googleapis/mcp toolbox
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 9.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2026-11720

To remediate this vulnerability, upgrade all affected Github.com/googleapis/mcp toolbox dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

github.com/googleapis/mcp-toolbox fixed: 1.3.0 
Upgrade github.com/googleapis/mcp-toolbox to 1.3.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for github.com/googleapis/mcp-toolbox

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-11720, inspect your project dependencies for Github.com/googleapis/mcp toolbox:

inspect dependencies for github.com/googleapis/mcp-toolbox

Analyze the terminal output to locate any version of Github.com/googleapis/mcp toolbox in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.3.0), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'), where the product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. In Github.com/googleapis/mcp toolbox, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

A path traversal vulnerability exists in the HTTP tool URL builder of googleapis/mcp-toolbox. When constructing downstream API requests, the URL builder substitutes user-controlled pathParams into the configured tool path and parses the resulting string as a relative URL. While it checks that the input does not alter the scheme, host, or user info, it relies on ResolveReference for the final URL resolution. Because dot segments (../) are normalized during this resolution step, an attacker can supply path parameters containing directory traversal sequences to escape the operator-configured path scope. This allows the client to coerce the toolbox into making requests to unintended endpoints on the same target host while forwarding the toolbox's configured credentials (e.g., bypassing a restricted path like /api/v1/users/{{.id}} to reach /admin/secrets).

CVE-2026-11720 Affected Github.com/googleapis/mcp toolbox Versions

1 component(s)
Fixed Versions:
1.3.0
Product / Package Ecosystem Affected Versions Fixed Version
github.com/googleapis/mcp-toolbox
golang/github.com/googleapis/mcp-toolbox
Go
< 1.3.0
1.3.0

References

NVD — CVE-2026-11720 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-11720
Github.com/googleapis/mcp toolbox Source Repository REPOSITORY
https://github.com/googleapis/mcp-toolbox/pull/3218
Security Fix Commit FIX COMMIT
https://github.com/googleapis/mcp-toolbox/commit/80a66021205e032a424fff87b3dc6d92da58aa77
Github.com/googleapis/mcp toolbox Source Repository REPOSITORY
https://github.com/googleapis/mcp-toolbox
Github.com/googleapis/mcp toolbox Release RELEASE
https://github.com/googleapis/mcp-toolbox/releases/tag/v1.3.0

Frequently Asked Questions

What is CVE-2026-11720?
CVE-2026-11720 is a security vulnerability in Github.com/googleapis/mcp toolbox involving MCP Toolbox HTTP tool path parameters allow traversal to unintended endpoints under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal').
Which Github.com/googleapis/mcp toolbox versions are affected?
Affected versions include releases prior to 1.3.0 across affected packages: github.com/googleapis/mcp-toolbox.
What version fixes CVE-2026-11720?
Upgrading to 1.3.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/googleapis/mcp-toolbox affected?
Yes, github.com/googleapis/mcp-toolbox is affected in releases prior to 1.3.0. Upgrade your dependency to 1.3.0 or later.
What is the CVSS score of CVE-2026-11720?
CVE-2026-11720 has a CVSS v3.1 base score of 9.1 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.
What CWE is associated with CVE-2026-11720?
CVE-2026-11720 is classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') (The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.).
How can I check Go dependencies for CVE-2026-11720?
Run the dependency tree command: 'inspect dependencies for github.com/googleapis/mcp-toolbox'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-vwxw-jrg6-9jxv",
  "modified" : "2026-09-04T19:21:10Z",
  "published" : "2026-06-29T18:31:55Z",
  "aliases" : [ "CVE-2026-11720" ],
  "summary" : "MCP Toolbox HTTP tool path parameters allow traversal to unintended endpoints",
  "details" : "A path traversal vulnerability exists in the HTTP tool URL builder of googleapis/mcp-toolbox.\n\nWhen constructing downstream API requests, the URL builder substitutes user-controlled pathParams into the configured tool path and parses the resulting string as a relative URL. While it checks that the input does not alter the scheme, host, or user info, it relies on ResolveReference for the final URL resolution. Because dot segments (../) are normalized during this resolution step, an attacker can supply path parameters containing directory traversal sequences to escape the operator-configured path scope. This allows the client to coerce the toolbox into making requests to unintended endpoints on the same target host while forwarding the toolbox's configured credentials (e.g., bypassing a restricted path like /api/v1/users/{{.id}} to reach /admin/secrets).",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "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"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/googleapis/mcp-toolbox"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.3.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-11720"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/googleapis/mcp-toolbox/pull/3218"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/googleapis/mcp-toolbox/commit/80a66021205e032a424fff87b3dc6d92da58aa77"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/googleapis/mcp-toolbox"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/googleapis/mcp-toolbox/releases/tag/v1.3.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-22" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-09-04T19:21:10Z",
    "nvd_published_at" : "2026-06-29T18:16:36Z"
  }
}