CVE-2026-4137

Description

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.

How to fix CVE-2026-4137

To remediate CVE-2026-4137, upgrade the affected package to a fixed version below.

• —upgrade to 3.11.0 or later
• —upgrade to 3.11.0 or later

Is CVE-2026-4137 being exploited?

Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.

Affected packages (2)

• from 0, < 3.11.0
• from 0, < 3.11.0

CVSS scores

References (5)

• ADVISORYgithub.com/advisories/GHSA-4x5p-f36r-mxxr
• ADVISORYnvd.nist.gov/vuln/detail/CVE-2026-4137
• PATCHgithub.com/mlflow/mlflow
• WEBgithub.com/mlflow/mlflow/commit/1dcbb0c2fbd1f446c328830e601ca13a28219b8a
• WEB