CVE-2026-52870

{
  "id": "CVE-2026-52870",
  "sourceIdentifier": "[email protected]",
  "published": "2026-07-15T20:17:38.577",
  "lastModified": "2026-10-24T21:10:00.130",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol (MCP). From 1.23.0 until 1.27.2, default handlers installed by server.experimental.enable_tasks() for tasks/list, tasks/get, tasks/result, and tasks/cancel operate only on task identifiers without recording the session that created each task, allowing any connected client to enumerate, read results from, consume messages for, or cancel other clients' tasks. This issue is fixed in version 1.27.2."
    },
    {
      "lang": "es",
      "value": "El SDK de Python de MCP, llamado ’mcp’ en PyPI, es una implementación en Python del Protocolo de Contexto de Modelo (MCP). Desde la versión 1.23.0 hasta la 1.27.2, los manejadores predeterminados instalados por server.experimental.enable_tasks() para tasks/list, tasks/get, tasks/result y tasks/cancel operan solo en identificadores de tarea sin registrar la sesión que creó cada tarea, permitiendo a cualquier cliente conectado enumerar, leer resultados de, consumir mensajes para, o cancelar las tareas de otros clientes. Este problema está solucionado en la versión 1.27.2."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "modelcontextprotocol",
          "product": "python-sdk",
          "versions": [
            {
              "version": ">= 1.23.0, < 1.27.2",
              "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:L/A:L",
          "baseScore": 7.6,
          "baseSeverity": "HIGH",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "LOW",
          "availabilityImpact": "LOW"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 4.7
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-07-16T13:01:33.294977Z",
          "id": "CVE-2026-52870",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-862"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:lfprojects:mcp_python_sdk:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "1.23.0",
              "versionEndExcluding": "1.27.2",
              "matchCriteriaId": "788DA6BA-F84C-4AFA-B31F-7096732011C8"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/modelcontextprotocol/python-sdk/commit/62137874ff26dd74d2fea80ff528a7fd9ca7a5e7",
      "source": "[email protected]",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://github.com/modelcontextprotocol/python-sdk/pull/2720",
      "source": "[email protected]",
      "tags": [
        "Issue Tracking",
        "Patch"
      ]
    },
    {
      "url": "https://github.com/modelcontextprotocol/python-sdk/releases/tag/v1.27.2",
      "source": "[email protected]",
      "tags": [
        "Release Notes"
      ]
    },
    {
      "url": "https://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-hvrp-rf83-w775",
      "source": "[email protected]",
      "tags": [
        "Vendor Advisory"
      ]
    }
  ]
}