Vulnerability · Published May 15, 2026 · Assigned by @huntr_ai
CVE-2026-2652Authentication Bypass in mlflow/mlflow
High 8.6
In plain English
A high-severity security flaw in mlflow/mlflow from mlflow. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 20.8% (higher than 98% of all known vulnerabilities). Ready-made attack tooling exists: Nuclei. Fixed versions are available - upgrade the affected package.
Official description
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 (`--app-name basic-auth`) and served via uvicorn (ASGI). The FastAPI permission middleware only enforces authentication on `/gateway/` routes, leaving other routes such as the Job API (`/ajax-api/3.0/jobs/*`) and the OpenTelemetry trace ingestion API (`/v1/traces`) 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 `_find_fastapi_validator()` function fails to handle non-`/gateway/` paths, resulting in a complete authentication bypass. This vulnerability is fixed in version 3.10.0.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | mlflow | 3.11.0 | GHSA-75cm-x2w3-8mgf |
| PyPI | mlflow | 3.10.0 | PYSEC-2026-2221 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| mlflow | mlflow/mlflow | unspecified – before 3.10.0 |
Weakness: CWE-305 · Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L