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Vulnerability · CVE-2026-2652

lfprojects mlflow Authentication Bypass by Primary Weakness

Published May 15, 2026 · corrected/updated Aug 7, 2026 · lfprojects mlflow · evidence confidence very high

A vulnerability in mlflow/mlflow versions 3.9.0 and earlier allows unauthenticated access to certain FastAPI routes when the server is started with authentication enabled ( ) and served via uvicorn (ASGI). The FastAPI permission middleware only enforces authentication on routes, leaving other routes such as the Job API ( ) and the OpenTelemetry trace ingestion API ( ) unprotected. This allows unauthenticated remote attackers to submit jobs, read job results, cancel running jobs, and inject arbitrary trace data into experiments. The issue arises from an architectural mismatch between Flask and FastAPI authentication mechanisms, where the function fails to handle non- paths, resulting in a complete authentication bypass. This vulnerability is fixed in version 3.10.0.

Grounded briefings

Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.

Executive

CVE-2026-2652 is a high public vulnerability record for lfprojects mlflow. CISA lists it as known exploited. Published remediation guidance: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.

System administrator

Identify whether lfprojects mlflow is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: lfprojects/mlflow; lfprojects mlflow. Published remediation guidance: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.

Security analyst

Signals on file: CVSS 8.6, EPSS 1.4%. CISA lists it as known exploited. Weakness classes: CWE-305. Sources contributing to this record: cve_org, epss, nvd, vulncheck_kev. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.

Exploitation and remediation

  • Exploitation evidence

    Confirmed in CISA KEV since Aug 7, 2026. Listed in CISA KEV and VulnCheck KEV.

  • Patch and remediation

    Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

  • Safe detection guidance

    Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. May 15, 2026 · NIST NVD

    Detected

    A vulnerability in mlflow/mlflow versions 3.9.0 and earlier allows unauthenticated access to certain FastAPI routes when the server is started with authentication enabled ( ) and served via uvicorn (ASGI). The FastAPI permission middleware only enforces authentication on routes, leaving other routes such as the Job API ( ) and the OpenTelemetry trace ingestion API ( ) unprotected. This allows unau

  2. Jun 17, 2026 · NIST NVD

    Updated

    A vulnerability in mlflow/mlflow versions 3.9.0 and earlier allows unauthenticated access to certain FastAPI routes when the server is started with authentication enabled ( ) and served via uvicorn (ASGI). The FastAPI permission middleware only enforces authentication on routes, leaving other routes such as the Job API ( ) and the OpenTelemetry trace ingestion API ( ) unprotected. This allows unau

  3. Aug 7, 2026 · CISA KEV

    Known exploited

    Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

  4. Aug 7, 2026 · VulnCheck KEV

    Updated

    A vulnerability in mlflow/mlflow versions 3.9.0 and earlier allows unauthenticated access to certain FastAPI routes when the server is started with authentication enabled ( ) and served via uvicorn (ASGI). The FastAPI permission middleware only enforces authentication on routes, leaving other routes such as the Job API ( ) and the OpenTelemetry trace ingestion API ( ) unprotected. This allows unau

Affected

  • cpe lfprojects/mlflowversion unspecified
  • vendor lfprojects mlflowversion unspecified

Sources

  • CVE.orgVulnerability recordCVE-2026-2652

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-2652

    30-day exploitation probability 1.4%

    first.org
  • NIST NVDVulnerability recordCVE-2026-2652

    A vulnerability in mlflow/mlflow versions 3.9.0 and earlier allows unauthenticated access to certain FastAPI routes when the server is started with authentication enabled ( ) and served via uvicorn (ASGI). The FastAPI permission middleware only enforces auth

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2026-2652

    A vulnerability in mlflow/mlflow versions 3.9.0 and earlier allows unauthenticated access to certain FastAPI routes when the server is started with authentication enabled ( ) and served via uvicorn (ASGI). The FastAPI permission middleware only enforces authentication on routes,

    vulncheck.com

References