CVE-2026-3198: MLflow Any Authenticated User Can Enumerate Vulnerability

MODERATE
Advisory Identifier: GHSA-r5m9-wm49-959f
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CVSS 6.5
CWE-284
Published
Advisory Summary

CVE-2026-3198 is a MODERATE (CVSS 6.5) any authenticated user can enumerate vulnerability (CWE-284: Improper Access Control) affecting MLflow libraries in the PyPI ecosystem. The issue involves any authenticated user can enumerate all gateway secrets, endpoints, and model definitions. Remediation is available by upgrading affected packages to version 3.11.0rc0.

CVE-2026-3198 at a Glance

CVE Identifier CVE-2026-3198
GHSA Identifier GHSA-r5m9-wm49-959f
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-2026-3198

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: 3.11.0rc0 
pip install mlflow>=3.11.0rc0
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-2026-3198, 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 3.11.0rc0), 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

MLflow 3.9.0 with basic-auth (`--app-name basic-auth`) fails to enforce authorization checks for multiple Gateway API 'list' endpoints. Specifically, the `BEFORE_REQUEST_HANDLERS` dictionary in `mlflow/server/auth/__init__.py` does not include entries for `ListGatewaySecretInfos`, `ListGatewayEndpoints`, and `ListGatewayModelDefinitions`. This allows any authenticated user, regardless of their assigned permissions, to enumerate all gateway secrets, endpoints, and model definitions. This vulnerability exposes sensitive information, such as API keys, endpoint configurations, and proprietary model definitions, to unauthorized users.

CVE-2026-3198 Affected MLflow Versions

1 component(s)
Fixed Versions:
3.11.0rc0
Product / Package Ecosystem Affected Versions Fixed Version
mlflow
pypi/mlflow
PyPI
< 3.11.0rc0
3.11.0rc0

References

NVD — CVE-2026-3198 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-3198
Security Fix Commit FIX COMMIT
https://github.com/mlflow/mlflow/commit/6989066af33fdcb03588fd71a1a67f8fc5ef12c9
MLflow Source Repository REPOSITORY
https://github.com/mlflow/mlflow
huntr.com/bounties/e57db731-9... WEB
https://huntr.com/bounties/e57db731-97d3-40c3-a429-831ee959807f

Frequently Asked Questions

What is CVE-2026-3198?
CVE-2026-3198 is a security vulnerability in MLflow involving Any authenticated user can enumerate all gateway secrets, endpoints, and model definitions under CWE-284: Improper Access Control.
Which MLflow versions are affected?
Affected versions include releases prior to 3.11.0rc0 across affected packages: mlflow.
What version fixes CVE-2026-3198?
Upgrading to 3.11.0rc0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is mlflow affected?
Yes, mlflow is affected in releases prior to 3.11.0rc0. Upgrade your dependency to 3.11.0rc0 or later.
What is the CVSS score of CVE-2026-3198?
CVE-2026-3198 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-2026-3198?
CVE-2026-3198 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-2026-3198?
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-r5m9-wm49-959f",
  "modified" : "2026-07-09T20:52:00Z",
  "published" : "2026-06-02T06:30:26Z",
  "aliases" : [ "CVE-2026-3198" ],
  "summary" : "MLflow: Any authenticated user can enumerate all gateway secrets, endpoints, and model definitions",
  "details" : "MLflow 3.9.0 with basic-auth (`--app-name basic-auth`) fails to enforce authorization checks for multiple Gateway API 'list' endpoints. Specifically, the `BEFORE_REQUEST_HANDLERS` dictionary in `mlflow/server/auth/__init__.py` does not include entries for `ListGatewaySecretInfos`, `ListGatewayEndpoints`, and `ListGatewayModelDefinitions`. This allows any authenticated user, regardless of their assigned permissions, to enumerate all gateway secrets, endpoints, and model definitions. This vulnerability exposes sensitive information, such as API keys, endpoint configurations, and proprietary model definitions, to unauthorized users.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "mlflow"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.11.0rc0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-3198"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mlflow/mlflow/commit/6989066af33fdcb03588fd71a1a67f8fc5ef12c9"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/mlflow/mlflow"
  }, {
    "type" : "WEB",
    "url" : "https://huntr.com/bounties/e57db731-97d3-40c3-a429-831ee959807f"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-284" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-09T20:52:00Z",
    "nvd_published_at" : "2026-06-02T04:17:03Z"
  }
}