MLflow up to 3.9.x Multipart Upload /mlflow-artifacts/mpu/ authorization

Summaryinfo

A vulnerability was found in MLflow up to 3.9.x and classified as critical. Affected is an unknown function of the file /mlflow-artifacts/mpu/ of the component Multipart Upload Handler. Such manipulation leads to authorization. This vulnerability is traded as CVE-2026-2651. The attack may be launched remotely. There is no exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in MLflow up to 3.9.x. Affected by this issue is an unknown code of the file /mlflow-artifacts/mpu/ of the component Multipart Upload Handler. The manipulation with an unknown input leads to a authorization vulnerability. Using CWE to declare the problem leads to CWE-862. The product does not perform an authorization check when an actor attempts to access a resource or perform an action. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at huntr.com. This vulnerability is handled as CVE-2026-2651 since 02/18/2026. The exploitation is known to be easy. The attack may be launched remotely. Technical details are known, but there is no available exploit.

Upgrading to version 3.10.0 eliminates this vulnerability. Applying the patch d7290811d8f3c95366d80109424edc1fb1ad966f is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-31642). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Name

• MLflow

Version

• 3.0
• 3.1
• 3.2
• 3.3
• 3.4
• 3.5
• 3.6
• 3.7
• 3.8
• 3.9

License

• open-source

Website

• Product: https://github.com/mlflow/mlflow/

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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