CVE-2026-2734 Authorization Bypass in SearchModelVersions in mlflow/mlflow
Authenticated users can bypass per-model authorization to enumerate all model versions and metadata in MLflow when basic authentication is enabled.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-2734?
CVE-2026-2734 is a medium-severity missing authorization vulnerability in Lfprojects Mlflow, published on 21 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
In mlflow/mlflow versions up to 3.9.0, the `SearchModelVersions` REST API endpoint and the `mlflowSearchModelVersions` GraphQL query lack proper per-model authorization checks when basic authentication is enabled. This allows any authenticated user to enumerate all model versions across all registered models, regardless of their permission level. The issue arises due to the absence of `SearchModelVersions` in the `BEFORE_REQUEST_VALIDATORS` and `AFTER_REQUEST_HANDLERS` for the REST API, and its omission from `GraphQLAuthorizationMiddleware.PROTECTED_FIELDS` for GraphQL. This vulnerability can expose sensitive information such as model names, version descriptions, source URIs, tags, and other metadata, potentially revealing proprietary or confidential details in multi-tenant environments. The issue is resolved in version 3.10.0.
Weakness: CWE-284
Which versions are affected by CVE-2026-2734?
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 | 3.10.0 |
mlflow PyPI | All versions | 3.10.0 |
Products include Lfprojects Mlflow.
How do I fix CVE-2026-2734?
Upgrade mlflow to 3.10.0 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-2734 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-2734 exists.
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-2026-2734, CLSA-2026-1791447254, GHSA-w5xq-c4pf-ghq7, PYSEC-2026-2660.