CVE-2026-63119

{
  "id": "CVE-2026-63119",
  "sourceIdentifier": "[email protected]",
  "published": "2026-07-29T20:17:10.790",
  "lastModified": "2026-10-24T13:10:00.147",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StdioTransport and MCP::Client::Stdio in the mcp gem use IO#gets without a byte limit, allowing a peer that sends data without a newline to exhaust process memory. This issue is fixed in version 0.23.0."
    },
    {
      "lang": "es",
      "value": "MCP Ruby SDK es el SDK oficial de Ruby para servidores y clientes del Protocolo de Contexto de Modelo. Antes de la 0.23.0, MCP::Server::Transports::StdioTransport y MCP::Client::Stdio en la gema mcp usan IO#gets sin un límite de bytes, permitiendo que un par que envía datos sin un salto de línea agote la memoria del proceso. Este problema está solucionado en la versión 0.23.0."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "modelcontextprotocol",
          "product": "ruby-sdk",
          "versions": [
            {
              "version": "< 0.23.0",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "baseScore": 6.2,
          "baseSeverity": "MEDIUM",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 2.5,
        "impactScore": 3.6
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-07-29T19:28:33.562204Z",
          "id": "CVE-2026-63119",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-400"
        },
        {
          "lang": "en",
          "value": "CWE-770"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/modelcontextprotocol/ruby-sdk/commit/267b8fa6285453525c81ce43db6b7dcd7a8a8c2f",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v0.23.0",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-7683-3w9x-ch42",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-7683-3w9x-ch42",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
    }
  ]
}