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FKIE_CVE-2026-90898

Vulnerability from fkie_nvd - Published: 2026-09-14 11:17 - Updated: 2026-09-14 12:17
Severity
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
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.
References
reefs@jfrog.comhttps://github.com/maximhq/bifrost
reefs@jfrog.comhttps://github.com/maximhq/bifrost/commit/12e170352bd25eab1ae9ba16611f1797d1fd8fdc
reefs@jfrog.comhttps://github.com/maximhq/bifrost/pull/6757
reefs@jfrog.comhttps://github.com/maximhq/bifrost/releases/tag/transports/v2.1.0
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "collectionURL": "https://github.com/maximhq/bifrost",
          "defaultStatus": "unaffected",
          "modules": [
            "transports/bifrost-http",
            "core/mcp"
          ],
          "packageName": "github.com/maximhq/bifrost/transports",
          "platforms": [
            "Linux",
            "macOS"
          ],
          "product": "Bifrost",
          "programFiles": [
            "transports/bifrost-http/handlers/mcp.go",
            "transports/bifrost-http/handlers/middlewares.go"
          ],
          "repo": "git://github.com/maximhq/bifrost",
          "vendor": "maximhq",
          "versions": [
            {
              "lessThan": "2.1.0",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "reefs@jfrog.com"
    }
  ],
  "cveTags": [],
  "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\u00a0transports/v2.1.0 refuses an unauthenticated stdio registration with 403. transports/v2.0.0 still allows it."
    }
  ],
  "id": "CVE-2026-90898",
  "lastModified": "2026-09-14T12:17:51.657",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9,
        "source": "reefs@jfrog.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-90898",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-09-14T11:01:44.207374Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-09-14T11:17:08.237",
  "references": [
    {
      "source": "reefs@jfrog.com",
      "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"
    }
  ],
  "sourceIdentifier": "reefs@jfrog.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-284"
        },
        {
          "lang": "en",
          "value": "CWE-306"
        }
      ],
      "source": "reefs@jfrog.com",
      "type": "Secondary"
    }
  ]
}



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