FKIE_CVE-2026-4270

Vulnerability from fkie_nvd - Published: 2026-03-16 17:16 - Updated: 2026-05-21 15:58
Severity
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Summary
Improper Protection of Alternate Path exists in the no-access and workdir feature of the AWS API MCP Server versions >= 0.2.14 and < 1.3.9 on all platforms may allow the bypass of intended file access restriction and expose arbitrary local file contents in the MCP client application context. To remediate this issue, users should upgrade to version 1.3.9.
References
ff89ba41-3aa1-4d27-914a-91399e9639e5https://aws.amazon.com/security/security-bulletins/2026-007-AWS/Vendor Advisory
ff89ba41-3aa1-4d27-914a-91399e9639e5https://pypi.org/project/awslabs.aws-api-mcp-server/1.3.9/Third Party Advisory
Impacted products
Vendor Product Version
amazon aws_api_mcp_server *
To clipboard 

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:amazon:aws_api_mcp_server:*:*:*:*:*:python:*:*",
              "matchCriteriaId": "EE415FFE-9C17-4E1A-8608-7DAA348BDAA6",
              "versionEndExcluding": "1.3.9",
              "versionStartIncluding": "0.2.14",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Improper Protection of Alternate Path exists in the no-access and workdir feature of the AWS API MCP Server versions \u003e= 0.2.14 and \u003c 1.3.9 on all platforms may allow the bypass of intended file access restriction and expose arbitrary local file contents in the MCP client application context.\n\nTo remediate this issue, users should upgrade to version 1.3.9."
    },
    {
      "lang": "es",
      "value": "Protecci\u00f3n Inadecuada de Ruta Alternativa existe en la caracter\u00edstica no-access y workdir del servidor AWS API MCP versiones \u0026gt;= 0.2.14 y \u0026lt; 1.3.9 en todas las plataformas, lo que puede permitir la omisi\u00f3n de la restricci\u00f3n de acceso a archivos prevista y exponer contenidos de archivos locales arbitrarios en el contexto de la aplicaci\u00f3n cliente MCP.\n\nPara remediar este problema, los usuarios deben actualizar a la versi\u00f3n 1.3.9."
    }
  ],
  "id": "CVE-2026-4270",
  "lastModified": "2026-05-21T15:58:19.767",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "NONE",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6,
        "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5",
        "type": "Secondary"
      }
    ],
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "LOCAL",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 6.8,
          "baseSeverity": "MEDIUM",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "PASSIVE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "version": "4.0",
          "vulnAvailabilityImpact": "NONE",
          "vulnConfidentialityImpact": "HIGH",
          "vulnIntegrityImpact": "NONE",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-03-16T17:16:32.270",
  "references": [
    {
      "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5",
      "tags": [
        "Vendor Advisory"
      ],
      "url": "https://aws.amazon.com/security/security-bulletins/2026-007-AWS/"
    },
    {
      "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://pypi.org/project/awslabs.aws-api-mcp-server/1.3.9/"
    }
  ],
  "sourceIdentifier": "ff89ba41-3aa1-4d27-914a-91399e9639e5",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-424"
        }
      ],
      "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5",
      "type": "Secondary"
    }
  ]
}


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Sightings

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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.
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  • 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.