CVE-2026-2651: Mlflow MLflow Allows Unauthorized Access To Vulnerability

CRITICAL
Advisory Identifier: GHSA-8c7q-86fq-vvmh
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CVSS 9.0
CWE-1220 CWE-862
Published
Advisory Summary

CVE-2026-2651 is a CRITICAL (CVSS 9.0) mlflow allows unauthorized access to vulnerability (CWE-1220: Insufficient Granularity of Access Control) affecting Mlflow libraries in the PyPI ecosystem. The issue involves mlflow allows unauthorized access to multipart upload endpoints when the `--serve-artifacts` mode is enabled. Remediation is available by upgrading affected packages to version 3.10.0.

CVE-2026-2651 at a Glance

CVE Identifier CVE-2026-2651
GHSA Identifier GHSA-8c7q-86fq-vvmh
Severity CRITICAL
CVSS v3.1 Base Score 9.0
CWE Classification CWE-1220: Insufficient Granularity of Access Control
Affected Product Mlflow
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 9.0

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:R/S:C/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction Required (UI:R)
Scope Changed (S:C)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-2651

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-2026-2651, 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-1220: Insufficient Granularity of Access Control, where the product implements access controls via a policy or other feature with the intention to disable or restrict accesses (reads and/or writes) to assets in a system from untrusted agents. however, implemented access controls lack required granularity, which renders the control policy too broad because it allows accesses from unauthorized agents to the security-sensitive assets. 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

A vulnerability in MLflow versions <=3.10.1.dev0 allows unauthorized access to multipart upload (MPU) endpoints when the `--serve-artifacts` mode is enabled. The authorization logic does not enforce resource-level permission checks for `/mlflow-artifacts/mpu/*` endpoints, enabling attackers to overwrite artifacts belonging to other users. This can lead to unauthorized cross-user writes, model supply chain poisoning, and arbitrary code execution when compromised models are loaded. The issue is resolved in version 3.10.0.

CVE-2026-2651 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-2026-2651 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-2651
Security Fix Commit FIX COMMIT
https://github.com/mlflow/mlflow/commit/d7290811d8f3c95366d80109424edc1fb1ad966f
Mlflow Security Information SECURITY
https://access.redhat.com/security/cve/CVE-2026-2651
bugzilla.redhat.com/show_bug.cgi WEB
https://bugzilla.redhat.com/show_bug.cgi?id=2481117
GitHub Advisory / Wiki ADVISORY
https://github.com/advisories/GHSA-8c7q-86fq-vvmh
Mlflow Source Repository REPOSITORY
https://github.com/mlflow/mlflow
Mlflow Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/mlflow/PYSEC-2026-2220.yaml
huntr.com/bounties/65beb119-d... WEB
https://huntr.com/bounties/65beb119-d3e0-4e03-af2f-fa98f78f83dc
Mlflow Security Information SECURITY
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-2651.json

Frequently Asked Questions

What is CVE-2026-2651?
CVE-2026-2651 is a security vulnerability in Mlflow involving MLflow allows unauthorized access to multipart upload endpoints when the `--serve-artifacts` mode is enabled under CWE-1220: Insufficient Granularity of Access Control.
Which Mlflow versions are affected?
Affected versions include releases prior to 3.10.0 across affected packages: mlflow.
What version fixes CVE-2026-2651?
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-2026-2651?
CVE-2026-2651 has a CVSS v3.1 base score of 9.0 (CRITICAL) with vector string CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H.
What CWE is associated with CVE-2026-2651?
CVE-2026-2651 is classified under CWE-1220: Insufficient Granularity of Access Control (The product implements access controls via a policy or other feature with the intention to disable or restrict accesses (reads and/or writes) to assets in a system from untrusted agents. However, implemented access controls lack required granularity, which renders the control policy too broad because it allows accesses from unauthorized agents to the security-sensitive assets.).
How can I check PyPI dependencies for CVE-2026-2651?
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 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-8c7q-86fq-vvmh",
  "modified" : "2026-10-06T18:43:55Z",
  "published" : "2026-05-26T13:30:39Z",
  "aliases" : [ "CVE-2026-2651" ],
  "summary" : "MLflow allows unauthorized access to multipart upload endpoints when the `--serve-artifacts` mode is enabled",
  "details" : "A vulnerability in MLflow versions <=3.10.1.dev0 allows unauthorized access to multipart upload (MPU) endpoints when the `--serve-artifacts` mode is enabled. The authorization logic does not enforce resource-level permission checks for `/mlflow-artifacts/mpu/*` endpoints, enabling attackers to overwrite artifacts belonging to other users. This can lead to unauthorized cross-user writes, model supply chain poisoning, and arbitrary code execution when compromised models are loaded. The issue is resolved in version 3.10.0.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "mlflow"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.10.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-2651"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mlflow/mlflow/commit/d7290811d8f3c95366d80109424edc1fb1ad966f"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/security/cve/CVE-2026-2651"
  }, {
    "type" : "WEB",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2481117"
  }, {
    "type" : "ADVISORY",
    "url" : "https://github.com/advisories/GHSA-8c7q-86fq-vvmh"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/mlflow/mlflow"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/mlflow/PYSEC-2026-2220.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://huntr.com/bounties/65beb119-d3e0-4e03-af2f-fa98f78f83dc"
  }, {
    "type" : "WEB",
    "url" : "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-2651.json"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1220", "CWE-862" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-30T16:48:21Z",
    "nvd_published_at" : "2026-05-25T07:16:15Z"
  }
}