Vulnerability-Lookup

GHSA-7PF3-8XX7-RVHF

Vulnerability from github – Published: 2026-05-28 00:30 – Updated: 2026-07-01 20:54

Summary

MCP Toolbox for Databases vulnerable to DNS rebinding attacks

Details

Vulnerable to DNS rebinding attacks when using SSE (http://b/499408790). During the beta phase, we implemented allowed-origins and allowed-hosts flags to align with MCP security guidelines. However, the hardcoded Access-Control-Allow-Origin: * header in the SSE initialization handler was inadvertently retained. This vulnerability specifically impacts users connecting via Toolbox using SSE under specification v2024-11-05.

Severity

9.4 (Critical)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/googleapis/mcp-toolbox"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.2.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-9739"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-942"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-01T20:54:22Z",
    "nvd_published_at": "2026-05-27T23:16:48Z",
    "severity": "CRITICAL"
  },
  "details": "Vulnerable to DNS rebinding attacks when using SSE (http://b/499408790). During the beta phase, we implemented `allowed-origins` and `allowed-hosts` flags to align with MCP security guidelines. However, the hardcoded `Access-Control-Allow-Origin: *` header in the SSE initialization handler was inadvertently retained. This vulnerability specifically impacts users connecting via Toolbox using SSE under specification v2024-11-05.",
  "id": "GHSA-7pf3-8xx7-rvhf",
  "modified": "2026-07-01T20:54:22Z",
  "published": "2026-05-28T00:30:29Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-9739"
    },
    {
      "type": "WEB",
      "url": "https://github.com/googleapis/mcp-toolbox/issues/3053"
    },
    {
      "type": "WEB",
      "url": "https://github.com/googleapis/mcp-toolbox/pull/3054"
    },
    {
      "type": "WEB",
      "url": "https://github.com/googleapis/mcp-toolbox/commit/c4c7bd917e686de68e2be866cfe3872c3439efae"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/googleapis/mcp-toolbox"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H",
      "type": "CVSS_V4"
    }
  ],
  "summary": "MCP Toolbox for Databases vulnerable to DNS rebinding attacks"
}

CVE-2026-9739 (GCVE-0-2026-9739)

Vulnerability from cvelistv5 – Published: 2026-05-27 21:38 – Updated: 2026-05-28 13:20

Summary

Vulnerable to DNS rebinding attacks when using SSE (http://b/499408790). During the beta phase, we implemented `allowed-origins` and `allowed-hosts` flags to align with MCP security guidelines. However, the hardcoded `Access-Control-Allow-Origin: *` header in the SSE initialization handler was inadvertently retained. This vulnerability specifically impacts users connecting via Toolbox using SSE under specification v2024-11-05.

Severity

9.4 (Critical)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator (v2.0.3)

CWE

CWE-942 - Permissive Cross-domain Policy with Untrusted Domains

Assigner

Google

References

2 references

URL	Tags
https://github.com/googleapis/mcp-toolbox/issues/3053
https://github.com/googleapis/mcp-toolbox/pull/3054

Impacted products

1 product

Vendor	Product	Version
Google	MCP Toolbox for Databases	Affected: 0 , < PR 3054 (Fix CORS bypass) (custom)

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  "containers": {
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      {
        "metrics": [
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              "content": {
                "id": "CVE-2026-9739",
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                  {
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                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-28T13:19:37.204820Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
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          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-28T13:20:43.816Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
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          "vendor": "Google",
          "versions": [
            {
              "lessThan": "PR 3054 (Fix CORS bypass)",
              "status": "affected",
              "version": "0",
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            }
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        }
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      "impacts": [
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          "descriptions": [
            {
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      "metrics": [
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            "Recovery": "NOT_DEFINED",
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            "exploitMaturity": "NOT_DEFINED",
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            "subAvailabilityImpact": "HIGH",
            "subConfidentialityImpact": "HIGH",
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            "userInteraction": "ACTIVE",
            "valueDensity": "NOT_DEFINED",
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          "url": "https://github.com/googleapis/mcp-toolbox/issues/3053"
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      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "x_generator": {
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  "cveMetadata": {
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    "dateReserved": "2026-05-27T17:31:41.604Z",
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-7PF3-8XX7-RVHF

CVE-2026-9739 (GCVE-0-2026-9739)

Tags

Sightings

Nomenclature