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CVE-2026-4137

Lfprojects Mlflow insecure deserialization

7.8 HIGHPublic exploitEPSS 0.16%
  1. Published18 May 2026

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.

CVSS 3.1 breakdown

Attack vectorLocal
Attack complexityLow
Privileges requiredLow
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

Lfprojects Mlflow< 3.11.0

Remediation

Fixed in
Lfprojects Mlflow≥ 3.11.0

References

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Frequently asked

Is CVE-2026-4137 being actively exploited?

CVE-2026-4137 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.16%.

How severe is CVE-2026-4137?

CVE-2026-4137 has a CVSS 3.1 base score of 7.8, rated high. EPSS estimates a 0.16% probability of exploitation.

Which products are affected by CVE-2026-4137?

Affected products include Lfprojects Mlflow.

How do I fix CVE-2026-4137?

Upgrade affected software to a fixed version, for example Lfprojects Mlflow 3.11.0 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-4137 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.