Authorization Bypass in MLflow AJAX Endpoint

{
  "id": "578ad4d842a0519748050be209b8d4a968d9ab73cc3ea90fdfedd759d4ed17cb",
  "url": "https://osv.dev/vulnerability/CVE-2026-33866",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Authorization Bypass in MLflow AJAX Endpoint",
    "summary": "MLflow is vulnerable to an authorization bypass affecting the AJAX endpoint used to download saved model artifacts. Due to missing access‑control validation, a user without permissions to a given experiment can directly query this endpoint and retrieve model artifacts they are not authorized to access. This issue affects MLflow version through 3.10.1",
    "evidence": "osv:CVE-2026-33866",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-33866",
      "aliases": [
        "BIT-mlflow-2026-33866",
        "CVE-2026-33866",
        "GHSA-46r5-x6jq-v8g6",
        "PYSEC-2026-94"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/mlflow/mlflow",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "cadc323c059d08ee15c3a312afd0eefeeccedc94"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "3.10.1"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "cpe": "cpe:2.3:a:lfprojects:mlflow:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "3.10.1"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v3.10.1",
            "v3.10.0",
            "v3.10.0rc0",
            "nightly",
            "v3.0.0",
            "v2.2.0",
            "v1.7.0",
            "1.0.0",
            "v0.8.1",
            "v0.8.0",
            "v0.7",
            "v0.6.0",
            "v0.5.0",
            "v0.4.2",
            "v0.4.1",
            "v0.4.0",
            "v0.3.0",
            "v0.2.1",
            "v0.2.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33866.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:43.282015403Z",
      "provider": "osv",
      "references": [
        "https://github.com/",
        "https://github.com/mlflow/",
        "https://cert.pl/en/posts/2026/04/CVE-2026-33865/",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33866.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-33866",
        "https://github.com/mlflow/mlflow/pull/21708",
        "https://afine.com/blogs/attacking-mlflow-how-ml-artifacts-become-attack-vectors"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-862"
        ],
        "cna_assigner": "CERT-PL",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33866.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-33866",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 510911,
  "published_at": "2026-04-07T12:57:44.38+00:00"
}