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CVE-2026-90898

Estado: Pendiente de análisisCrítica (9.8)—

Bifrost registers MCP clients through its management API. A stdio client is a command plus args. Bifrost starts that program in the gateway the moment the client is added. No MCP handshake required.

The default is governance.auth_config.is_enabled=false. Auth off means every caller is a local admin. One unauthenticated POST /api/mcp/client is enough to run a program as the Bifrost process user (appuser on the official image).

transports/v2.1.0 refuses an unauthenticated stdio registration with 403. transports/v2.0.0 still allows it.

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

API expuesta sin autenticación (POST /api/mcp/client, auth_config.is_enabled=false) permite ejecutar programas arbitrarios como usuario del proceso Bifrost sin validación MCP. Vector CVSS AV:N/PR:N/UI:N confirma explotabilidad remota inmediata; CWE-284/306 (control de acceso débil) y la ausencia de

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Privileged Account ManagementApplication Developer GuidanceActive Directory ConfigurationVulnerability ScanningUser TrainingUser Account Management

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Xbifrost — BifrostAI

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-90898",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-90898",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-09-14T11:01:44.207374Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "reefs@jfrog.com",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.8,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "reefs@jfrog.com",
      "affectedData": [
        {
          "repo": "git://github.com/maximhq/bifrost",
          "vendor": "maximhq",
          "modules": [
            "transports/bifrost-http",
            "core/mcp"
          ],
          "product": "Bifrost",
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "lessThan": "2.1.0",
              "versionType": "semver"
            }
          ],
          "platforms": [
            "Linux",
            "macOS"
          ],
          "packageName": "github.com/maximhq/bifrost/transports",
          "programFiles": [
            "transports/bifrost-http/handlers/mcp.go",
            "transports/bifrost-http/handlers/middlewares.go"
          ],
          "collectionURL": "https://github.com/maximhq/bifrost",
          "defaultStatus": "unaffected"
        }
      ]
    }
  ],
  "published": "2026-09-14T11:17:08.237",
  "references": [
    {
      "url": "https://github.com/maximhq/bifrost",
      "source": "reefs@jfrog.com"
    },
    {
      "url": "https://github.com/maximhq/bifrost/commit/12e170352bd25eab1ae9ba16611f1797d1fd8fdc",
      "source": "reefs@jfrog.com"
    },
    {
      "url": "https://github.com/maximhq/bifrost/pull/6757",
      "source": "reefs@jfrog.com"
    },
    {
      "url": "https://github.com/maximhq/bifrost/releases/tag/transports/v2.1.0",
      "source": "reefs@jfrog.com"
    }
  ],
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "reefs@jfrog.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-284"
        },
        {
          "lang": "en",
          "value": "CWE-306"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Bifrost registers MCP clients through its management API. A stdio client is a command plus args. Bifrost starts that program in the gateway the moment the client is added. No MCP handshake required.\n\n\n\nThe default is governance.auth_config.is_enabled=false. Auth off means every caller is a local admin. One unauthenticated POST /api/mcp/client is enough to run a program as the Bifrost process user (appuser on the official image).\n\n\n\n transports/v2.1.0 refuses an unauthenticated stdio registration with 403. transports/v2.0.0 still allows it."
    }
  ],
  "lastModified": "2026-09-18T19:31:11.370",
  "sourceIdentifier": "reefs@jfrog.com"
}