CVE-2026-2652 Authentication Bypass in mlflow/mlflow
Unauthenticated attackers can access job and trace APIs in MLflow when using uvicorn with basic auth, allowing job submission and data injection.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-2652?
CVE-2026-2652 is a high-severity authentication bypass vulnerability in Lfprojects Mlflow, published on 15 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-305
Which versions are affected by CVE-2026-2652?
4 open source packages ship an affected version, including mlflow. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
mlflow Bitnami | All versions | 3.10.0 |
mlflow PyPI | All versions | 3.10.0 |
mlflow PyPI | All versions | 3.11.0 |
mlflow PyPI | All versions | 3.11.0 |
Products include Lfprojects Mlflow.
How do I fix CVE-2026-2652?
Upgrade mlflow to a fixed version for your release line: 3.10.0 or 3.11.0.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-2652 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-2652 exists.
Public exploit code: 1 Nuclei template.
Other vulnerabilities in Lfprojects Mlflow
- CVE-2026-64849 MLflow Server-Side Request Forgery
- CVE-2025-15379 Command Injection in mlflow/mlflow
- CVE-2024-0520 Remote Code Execution due to Full Controlled File Write in mlflow/mlflow
- CVE-2023-6977 Path Traversal: '\..\filename'
- CVE-2023-6709 Improper Neutralization of Special Elements Used in a Template Engine in mlflow/mlflow
Sources
Also known as BIT-mlflow-2026-2652, GHSA-75cm-x2w3-8mgf, PYSEC-2026-2221.