CVE-2026-2734: Mlflow MLflow Authenticated Users Can Enumerate Vulnerability

MODERATE
Advisory Identifier: GHSA-w5xq-c4pf-ghq7
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CVSS 6.5
CWE-284
Published
Advisory Summary

CVE-2026-2734 is a MODERATE (CVSS 6.5) mlflow authenticated users can enumerate vulnerability (CWE-284: Improper Access Control) affecting Mlflow libraries in the PyPI ecosystem. The issue involves mlflow authenticated users can enumerate any registered model versions due to lack of per-model permissions checks. Remediation is available by upgrading affected packages to version 3.10.0.

CVE-2026-2734 at a Glance

CVE Identifier CVE-2026-2734
GHSA Identifier GHSA-w5xq-c4pf-ghq7
Severity MODERATE
CVSS v3.1 Base Score 6.5
CWE Classification CWE-284: Improper Access Control
Affected Product Mlflow
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 6.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity None (I:N)
Availability None (A:N)

How to Fix CVE-2026-2734

To remediate this vulnerability, upgrade all affected Mlflow dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

mlflow fixed: 3.10.0 
pip install mlflow>=3.10.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show mlflow

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2026-2734, inspect your installed packages using pip:

pip show mlflow

Analyze the terminal output to locate any version of Mlflow in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.10.0), your application is affected.

Note: The pip show mlflow command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-284: Improper Access Control, where the product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. In Mlflow, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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.

CVE-2026-2734 Affected Mlflow Versions

1 component(s)
Fixed Versions:
3.10.0
Product / Package Ecosystem Affected Versions Fixed Version
mlflow
pypi/mlflow
PyPI
< 3.10.0
3.10.0

References

NVD — CVE-2026-2734 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-2734
Security Fix Commit FIX COMMIT
https://github.com/mlflow/mlflow/commit/6989066af33fdcb03588fd71a1a67f8fc5ef12c9
Mlflow Source Repository REPOSITORY
https://github.com/mlflow/mlflow
huntr.com/bounties/d632f783-b... WEB
https://huntr.com/bounties/d632f783-b2c7-4a3b-af5e-1d693e841c08

Frequently Asked Questions

What is CVE-2026-2734?
CVE-2026-2734 is a security vulnerability in Mlflow involving MLflow authenticated users can enumerate any registered model versions due to lack of per-model permissions checks under CWE-284: Improper Access Control.
Which Mlflow versions are affected?
Affected versions include releases prior to 3.10.0 across affected packages: mlflow.
What version fixes CVE-2026-2734?
Upgrading to 3.10.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is mlflow affected?
Yes, mlflow is affected in releases prior to 3.10.0. Upgrade your dependency to 3.10.0 or later.
What is the CVSS score of CVE-2026-2734?
CVE-2026-2734 has a CVSS v3.1 base score of 6.5 (MODERATE) with vector string CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.
What CWE is associated with CVE-2026-2734?
CVE-2026-2734 is classified under CWE-284: Improper Access Control (The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.).
How can I check PyPI dependencies for CVE-2026-2734?
Run the dependency tree command: 'pip show mlflow'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
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  "schema_version" : "1.4.0",
  "id" : "GHSA-w5xq-c4pf-ghq7",
  "modified" : "2026-06-12T15:05:41Z",
  "published" : "2026-05-21T06:31:31Z",
  "aliases" : [ "CVE-2026-2734" ],
  "summary" : "MLflow authenticated users can enumerate any registered model versions due to lack of per-model permissions checks",
  "details" : "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.",
  "severity" : [ {
    "type" : "CVSS_V3",
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  } ],
  "affected" : [ {
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  "references" : [ {
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  "database_specific" : {
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    "severity" : "MODERATE",
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}