{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "0.3.2"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "577306d78190622eee97e362b042a69499ef373f"
            },
            {
              "fixed": "6455588e54cbbc32742852c652c35def6fa605c6"
            }
          ],
          "repo": "https://github.com/geiserx/genieacs-mcp",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-cmwv-wf9p-p8wx"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-346"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55637.json"
  },
  "details": "genieacs-mcp is an MCP server for GenieACS written in Go. Prior to 0.3.2, the Streamable HTTP transport in cmd/server/main.go creates an unauthenticated /mcp listener on the default MCP_LISTEN_ADDR value 127.0.0.1:8080 when MCP_AUTH_TOKEN is unset and the httpSrv.Start(addr) branch does not validate the Host or Origin headers. A malicious website can use DNS rebinding to send browser requests with attacker-controlled Host and Origin values to the loopback listener, initialize an MCP session, list tools, and invoke operations against the GenieACS NBI configured by ACS_URL. Successful exploitation can expose or modify CPE management state, including device reboots, firmware tasks, TR-069 parameter changes, presets, provisions, tags, connection requests, and task operations. The npm wrapper is not affected because it forces TRANSPORT=stdio and does not expose an HTTP listener. This issue is fixed in version 0.3.2.",
  "id": "CVE-2026-55637",
  "modified": "2026-09-11T03:30:41.935008714Z",
  "published": "2026-08-25T18:03:34.701Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/GeiserX/genieacs-mcp/releases/tag/v0.3.2"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55637.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/GeiserX/genieacs-mcp/security/advisories/GHSA-cmwv-wf9p-p8wx"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-55637"
    },
    {
      "type": "FIX",
      "url": "https://github.com/GeiserX/genieacs-mcp/commit/577306d78190622eee97e362b042a69499ef373f"
    },
    {
      "type": "FIX",
      "url": "https://github.com/GeiserX/genieacs-mcp/pull/26"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "genieacs-mcp: DNS rebinding reaches local GenieACS MCP Streamable HTTP transport"
}