CVE-2026-4137
HIGHDescription
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
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Exploit Intelligence
Low risk: more likely to be exploited than 9% of all known CVEs.
References
Related Vulnerabilities
Other CWE-378 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2020-27216 | High | 7.0 | 4.4% | - | Fix |
| CVE-2021-21290 | Medium | 6.2 | 1.8% | - | Fix |
| CVE-2016-9485 | High | 7.8 | 1.2% | - | - |
| CVE-2022-24823 | Medium | 5.5 | 1.0% | - | Fix |
| CVE-2020-8908 | Low | 3.3 | 1.0% | - | Fix |
| CVE-2021-28168 | Medium | 6.2 | 0.9% | - | Fix |
Common questions
How do I fix CVE-2026-4137?
Upgrade mlflow to 3.11.0 or later.
Is CVE-2026-4137 being actively exploited?
Not that we know of. CVE-2026-4137 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.19% is the estimated probability that it will be exploited in the next 30 days. That is higher than 9% of all scored CVEs.
How severe is CVE-2026-4137?
CVE-2026-4137 has a CVSS v3 base score of 7.8, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-4137 affect?
Published advisories record a fix for mlflow (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2026-4137
Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-07-24.