Flyto2 Core: Unauthenticated Command Execution via HTTP MCP `execute_module`

{
  "id": "c957eb0ad9700fa33a15df3a3530a81813e0e36ad3e0fcf39c5ae27e1f1c81b2",
  "url": "https://osv.dev/vulnerability/CVE-2026-55786",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Flyto2 Core: Unauthenticated Command Execution via HTTP MCP `execute_module`",
    "summary": "Flyto2 Core is an execution kernel for automation and AI-agent workflows. From 2.26.2 until 2.26.4, the HTTP MCP POST /mcp route accepts unauthenticated JSON-RPC tools/call requests and forwards execute_module arguments to the module registry without the require_auth dependency used by the REST execution routes. An unauthenticated caller can select sandbox.execute_shell and supply its command parameter, which reaches asyncio.create_subprocess_shell with the privileges of the flyto-core server process. The endpoint is reachable locally under the default loopback binding and becomes network reachable when an operator binds the server to a non-loopback interface, allowing arbitrary OS command execution and potential full host compromise. This issue is fixed in version 2.26.4.",
    "evidence": "osv:CVE-2026-55786",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-55786",
      "aliases": [
        "CVE-2026-55786",
        "GHSA-h9f9-h6gm-wc85",
        "PYSEC-2026-2482"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/flytohub/flyto-core",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "50d0d327a1278c8cec9495ba5f6f010dd67ef19c"
                },
                {
                  "fixed": "db7f116b1d3c5dcf94aded00d14118f81f3e225e"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "2.26.2"
                      },
                      {
                        "fixed": "2.26.4"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "db7f116b1d3c5dcf94aded00d14118f81f3e225e"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "50d0d327a1278c8cec9495ba5f6f010dd67ef19c"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v2.26.4"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v2.26.3",
            "v2.26.0",
            "v2.25.27",
            "v2.17.6",
            "v2.16.3",
            "v2.5.0",
            "v2.2.2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55786.json"
          }
        }
      ],
      "modified": "2026-10-31T02:31:06.952077652Z",
      "provider": "osv",
      "references": [
        "https://github.com/flytohub/flyto-core/releases/tag/v2.26.4",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55786.json",
        "https://github.com/flytohub/flyto-core/security/advisories/GHSA-h9f9-h6gm-wc85",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-55786",
        "https://github.com/flytohub/flyto-core/commit/db7f116b1d3c5dcf94aded00d14118f81f3e225e"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-306",
          "CWE-78"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55786.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-55786",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 514291,
  "published_at": "2026-10-14T18:14:39.21+00:00"
}