CVE-2026-4137 HIGH

CVE-2026-4137: Incomplete Fix for CVE-2025-10279: Insecure Temporary Directory Permissions in mlflow/mlflow

Vendor Mlflow
Product mlflow/mlflow
Weakness CWE-378
Published May 18, 2026
Last update May 19, 2026

CVSS base score

7.0/10
Attack vector Local
Attack complexity High
Privileges required Low
User interaction None
Confidentiality High
Integrity High

CVSS vector

CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

What the vulnerability does

01Description

In mlflow/mlflow versions prior to 3.11.0, the `get_or_create_nfs_tmp_dir()` function in `mlflow/utils/file_utils.py` creates temporary directories with world-writable permissions (0o777), and the `_create_model_downloading_tmp_dir()` function in `mlflow/pyfunc/__init__.py` creates directories with group-writable permissions (0o770). These insecure permissions allow local attackers to tamper with model artifacts, such as cloudpickle-serialized Python objects, and achieve arbitrary code execution when the tampered artifacts are deserialized via `cloudpickle.load()`. This vulnerability is particularly critical in environments with shared NFS mounts, such as Databricks, where NFS is enabled by default. The issue is a continuation of the vulnerability class addressed in CVE-2025-10279, which was only partially fixed.

Key dates

02Disclosure timeline

May 18, 2026 CVE published
May 19, 2026 Record updated