CVE-2026-39884

{
  "id": "CVE-2026-39884",
  "sourceIdentifier": "[email protected]",
  "published": "2026-04-15T04:17:37.097",
  "lastModified": "2026-10-26T22:10:00.163",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "mcp-server-kubernetes is a Model Context Protocol server for Kubernetes cluster management. Versions 3.4.0 and prior contain an argument injection vulnerability in the port_forward tool in src/tools/port_forward.ts, where a kubectl command is constructed via string concatenation with user-controlled input and then naively split on spaces before being passed to spawn(). Unlike all other tools in the codebase which correctly use array-based argument passing with execFileSync(), port_forward treats every space in user-controlled fields (namespace, resourceType, resourceName, localPort, targetPort) as an argument boundary, allowing an attacker to inject arbitrary kubectl flags. This enables exposure of internal Kubernetes services to the network by injecting --address=0.0.0.0, cross-namespace targeting by injecting additional -n flags, and indirect exploitation via prompt injection against AI agents connected to the MCP server. This issue has been fixed in version 3.5.0."
    },
    {
      "lang": "es",
      "value": "mcp-server-kubernetes es un servidor de Protocolo de Contexto de Modelo para la gestión de clústeres de Kubernetes. Las versiones 3.4.0 y anteriores contienen una vulnerabilidad de inyección de argumentos en la herramienta port_forward en src/tools/port_forward.ts, donde un comando kubectl se construye mediante concatenación de cadenas con entrada controlada por el usuario y luego se divide ingenuamente por espacios antes de ser pasado a spawn(). A diferencia de todas las demás herramientas en la base de código que utilizan correctamente el paso de argumentos basado en arrays con execFileSync(), port_forward trata cada espacio en los campos controlados por el usuario (namespace, resourceType, resourceName, localPort, targetPort) como un límite de argumento, permitiendo a un atacante inyectar flags kubectl arbitrarias. Esto permite la exposición de servicios internos de Kubernetes a la red inyectando --address=0.0.0.0, la segmentación entre namespaces inyectando flags -n adicionales, y la explotación indirecta mediante inyección de prompts contra agentes de IA conectados al servidor MCP. Este problema ha sido solucionado en la versión 3.5.0."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "Flux159",
          "product": "mcp-server-kubernetes",
          "versions": [
            {
              "version": "< 3.5.0",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L",
          "baseScore": 8.3,
          "baseSeverity": "HIGH",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "LOW"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.5
      },
      {
        "source": "[email protected]",
        "type": "Primary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N",
          "baseScore": 8.1,
          "baseSeverity": "HIGH",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "availabilityImpact": "NONE"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.2
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-04-15T16:04:43.245323Z",
          "id": "CVE-2026-39884",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-88"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:suyogs:mcp-server-kubernetes:*:*:*:*:*:node.js:*:*",
              "versionEndExcluding": "3.5.0",
              "matchCriteriaId": "D320AE00-0F25-4DFC-B553-81EF15C5BBC5"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/Flux159/mcp-server-kubernetes/releases/tag/v3.5.0",
      "source": "[email protected]",
      "tags": [
        "Product",
        "Release Notes"
      ]
    },
    {
      "url": "https://github.com/Flux159/mcp-server-kubernetes/security/advisories/GHSA-4xqg-gf5c-ghwq",
      "source": "[email protected]",
      "tags": [
        "Mitigation",
        "Vendor Advisory"
      ]
    },
    {
      "url": "https://github.com/Flux159/mcp-server-kubernetes/security/advisories/GHSA-4xqg-gf5c-ghwq",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "tags": [
        "Mitigation",
        "Vendor Advisory"
      ]
    }
  ]
}